Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultrathin, flexible fibers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and threading  them along the body's established pathways, physicians can look into the lungs, intestines,  heart and other areas that were formerly inaccessible to   them.
The basic fiber-optics system is called fiberscope, which consists of  two  bundles  of fibers. One, the illuminating bundle, carries light to the tissues. Is is coupled to  a  high- intensity light source. Light enters the cores of the high-purity silicon glass and travels along the fibers. A lens at the end of the bundle collects the light and  focuses  it into the other  bundle, the imaging bundle. Each fiber in the bundle transmits only a tiny fraction of the total image. The reconstructed image can be viewed through an eyepiece or displayed on a television screen.
During the last five years, improved methods of fabricating optical fibers have led to a reduction in fiberscope diameter and an increase in the number of fibers, which in turn has increased resolution. Optical fibers can also be used to deliver laser light. By use of laser beams, physicians can perform surgery inside the body, sometimes eliminating the need for invasive procedures in which healthy tissue must be cut through to reach the site of disease. Many of these procedures do not require anesthesia and can be performed in a physician's office. These techniques have reduced the risk and the cost of medical care.

Which of the following is NOT mentioned by the author as one of the advantages of laser surgery techniques?

Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultrathin, flexible fibers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and threading  them along the body's established pathways, physicians can look into the lungs, intestines,  heart and other areas that were formerly inaccessible to   them.
The basic fiber-optics system is called fiberscope, which consists of  two  bundles  of fibers. One, the illuminating bundle, carries light to the tissues. Is is coupled to  a  high- intensity light source. Light enters the cores of the high-purity silicon glass and travels along the fibers. A lens at the end of the bundle collects the light and  focuses  it into the other  bundle, the imaging bundle. Each fiber in the bundle transmits only a tiny fraction of the total image. The reconstructed image can be viewed through an eyepiece or displayed on a television screen.
During the last five years, improved methods of fabricating optical fibers have led to a reduction in fiberscope diameter and an increase in the number of fibers, which in turn has increased resolution. Optical fibers can also be used to deliver laser light. By use of laser beams, physicians can perform surgery inside the body, sometimes eliminating the need for invasive procedures in which healthy tissue must be cut through to reach the site of disease. Many of these procedures do not require anesthesia and can be performed in a physician's office. These techniques have reduced the risk and the cost of medical care.

The word resolution is closest in meaning to which of the following?

Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultrathin, flexible fibers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and threading  them along the body's established pathways, physicians can look into the lungs, intestines,  heart and other areas that were formerly inaccessible to   them.
The basic fiber-optics system is called fiberscope, which consists of  two  bundles  of fibers. One, the illuminating bundle, carries light to the tissues. Is is coupled to  a  high- intensity light source. Light enters the cores of the high-purity silicon glass and travels along the fibers. A lens at the end of the bundle collects the light and  focuses  it into the other  bundle, the imaging bundle. Each fiber in the bundle transmits only a tiny fraction of the total image. The reconstructed image can be viewed through an eyepiece or displayed on a television screen.
During the last five years, improved methods of fabricating optical fibers have led to a reduction in fiberscope diameter and an increase in the number of fibers, which in turn has increased resolution. Optical fibers can also be used to deliver laser light. By use of laser beams, physicians can perform surgery inside the body, sometimes eliminating the need for invasive procedures in which healthy tissue must be cut through to reach the site of disease. Many of these procedures do not require anesthesia and can be performed in a physician's office. These techniques have reduced the risk and the cost of medical care.

According to the passage, how do the fiberscopes used today differ from those used in five years ago?

Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultrathin, flexible fibers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and threading  them along the body's established pathways, physicians can look into the lungs, intestines,  heart and other areas that were formerly inaccessible to   them.
The basic fiber-optics system is called fiberscope, which consists of  two  bundles  of fibers. One, the illuminating bundle, carries light to the tissues. Is is coupled to  a  high- intensity light source. Light enters the cores of the high-purity silicon glass and travels along the fibers. A lens at the end of the bundle collects the light and  focuses  it into the other  bundle, the imaging bundle. Each fiber in the bundle transmits only a tiny fraction of the total image. The reconstructed image can be viewed through an eyepiece or displayed on a television screen.
During the last five years, improved methods of fabricating optical fibers have led to a reduction in fiberscope diameter and an increase in the number of fibers, which in turn has increased resolution. Optical fibers can also be used to deliver laser light. By use of laser beams, physicians can perform surgery inside the body, sometimes eliminating the need for invasive procedures in which healthy tissue must be cut through to reach the site of disease. Many of these procedures do not require anesthesia and can be performed in a physician's office. These techniques have reduced the risk and the cost of medical care.

Which of the following is closest in meaning to the word cores?

Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultrathin, flexible fibers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and threading  them along the body's established pathways, physicians can look into the lungs, intestines,  heart and other areas that were formerly inaccessible to   them.
The basic fiber-optics system is called fiberscope, which consists of  two  bundles  of fibers. One, the illuminating bundle, carries light to the tissues. Is is coupled to  a  high- intensity light source. Light enters the cores of the high-purity silicon glass and travels along the fibers. A lens at the end of the bundle collects the light and  focuses  it into the other  bundle, the imaging bundle. Each fiber in the bundle transmits only a tiny fraction of the total image. The reconstructed image can be viewed through an eyepiece or displayed on a television screen.
During the last five years, improved methods of fabricating optical fibers have led to a reduction in fiberscope diameter and an increase in the number of fibers, which in turn has increased resolution. Optical fibers can also be used to deliver laser light. By use of laser beams, physicians can perform surgery inside the body, sometimes eliminating the need for invasive procedures in which healthy tissue must be cut through to reach the site of disease. Many of these procedures do not require anesthesia and can be performed in a physician's office. These techniques have reduced the risk and the cost of medical care.

According to the passage, what is the purpose of the illuminating bundle in a fiberscope?

Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultrathin, flexible fibers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and threading  them along the body's established pathways, physicians can look into the lungs, intestines,  heart and other areas that were formerly inaccessible to   them.
The basic fiber-optics system is called fiberscope, which consists of  two  bundles  of fibers. One, the illuminating bundle, carries light to the tissues. Is is coupled to  a  high- intensity light source. Light enters the cores of the high-purity silicon glass and travels along the fibers. A lens at the end of the bundle collects the light and  focuses  it into the other  bundle, the imaging bundle. Each fiber in the bundle transmits only a tiny fraction of the total image. The reconstructed image can be viewed through an eyepiece or displayed on a television screen.
During the last five years, improved methods of fabricating optical fibers have led to a reduction in fiberscope diameter and an increase in the number of fibers, which in turn has increased resolution. Optical fibers can also be used to deliver laser light. By use of laser beams, physicians can perform surgery inside the body, sometimes eliminating the need for invasive procedures in which healthy tissue must be cut through to reach the site of disease. Many of these procedures do not require anesthesia and can be performed in a physician's office. These techniques have reduced the risk and the cost of medical care.

The word them in line 4 refers  to.................

Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultrathin, flexible fibers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and threading  them along the body's established pathways, physicians can look into the lungs, intestines,  heart and other areas that were formerly inaccessible to   them.
The basic fiber-optics system is called fiberscope, which consists of  two  bundles  of fibers. One, the illuminating bundle, carries light to the tissues. Is is coupled to  a  high- intensity light source. Light enters the cores of the high-purity silicon glass and travels along the fibers. A lens at the end of the bundle collects the light and  focuses  it into the other  bundle, the imaging bundle. Each fiber in the bundle transmits only a tiny fraction of the total image. The reconstructed image can be viewed through an eyepiece or displayed on a television screen.
During the last five years, improved methods of fabricating optical fibers have led to a reduction in fiberscope diameter and an increase in the number of fibers, which in turn has increased resolution. Optical fibers can also be used to deliver laser light. By use of laser beams, physicians can perform surgery inside the body, sometimes eliminating the need for invasive procedures in which healthy tissue must be cut through to reach the site of disease. Many of these procedures do not require anesthesia and can be performed in a physician's office. These techniques have reduced the risk and the cost of medical care.

Which of the following is closest in meaning to the word formerly?

Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultrathin, flexible fibers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and threading  them along the body's established pathways, physicians can look into the lungs, intestines,  heart and other areas that were formerly inaccessible to   them.
The basic fiber-optics system is called fiberscope, which consists of  two  bundles  of fibers. One, the illuminating bundle, carries light to the tissues. Is is coupled to  a  high- intensity light source. Light enters the cores of the high-purity silicon glass and travels along the fibers. A lens at the end of the bundle collects the light and  focuses  it into the other  bundle, the imaging bundle. Each fiber in the bundle transmits only a tiny fraction of the total image. The reconstructed image can be viewed through an eyepiece or displayed on a television screen.
During the last five years, improved methods of fabricating optical fibers have led to a reduction in fiberscope diameter and an increase in the number of fibers, which in turn has increased resolution. Optical fibers can also be used to deliver laser light. By use of laser beams, physicians can perform surgery inside the body, sometimes eliminating the need for invasive procedures in which healthy tissue must be cut through to reach the site of disease. Many of these procedures do not require anesthesia and can be performed in a physician's office. These techniques have reduced the risk and the cost of medical care.

In line 2, the author uses the expression have opened a window to indicate that the use of optical fibers

Just as optical fibers have transformed communication, they are also revolutionizing medicine. These ultrathin, flexible fibers have opened a window into the living tissues of the body. By inserting optical fibers through natural openings or small incisions and threading  them along the body's established pathways, physicians can look into the lungs, intestines,  heart and other areas that were formerly inaccessible to   them.
The basic fiber-optics system is called fiberscope, which consists of  two  bundles  of fibers. One, the illuminating bundle, carries light to the tissues. Is is coupled to  a  high- intensity light source. Light enters the cores of the high-purity silicon glass and travels along the fibers. A lens at the end of the bundle collects the light and  focuses  it into the other  bundle, the imaging bundle. Each fiber in the bundle transmits only a tiny fraction of the total image. The reconstructed image can be viewed through an eyepiece or displayed on a television screen.
During the last five years, improved methods of fabricating optical fibers have led to a reduction in fiberscope diameter and an increase in the number of fibers, which in turn has increased resolution. Optical fibers can also be used to deliver laser light. By use of laser beams, physicians can perform surgery inside the body, sometimes eliminating the need for invasive procedures in which healthy tissue must be cut through to reach the site of disease. Many of these procedures do not require anesthesia and can be performed in a physician's office. These techniques have reduced the risk and the cost of medical care.

What is the main topic of the  passage?

A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic through an area affects people in the way that a sudden increase in crime does. Appleyard observed this by finding three blocks of houses in San Francisco that looked much alike and had the same kind of middle-class and working-class residents, with approximately the same ethnic mix. The difference was that only 2,000 cars a day ran down Octavia Street (LIGHT street, in Appleyard’s terminology) while Gough Street (MEDIUM street) was used by 8,000 cars daily, and Franklin Street (HEAVY street) had around 16,000 cars a day. Franklin Street often had as many cars in an hour as Octavia had in a day.
Heavy traffic brought with it danger, noise, fumes and soot, directly, and trash secondarily. That is, the cars didn’t bring in much trash, but when trash accumulated, residents seldom picked it up. The cars, Appleyard determined, reduced the amount of territory residents felt responsible for. Noise was a constant intrusion into their homes. Many Franklin Street residents covered their doors and windows and spent most of their time in the rear of their houses. Most families with children had already left.
Conditions on Octavia Street were much different. Residents picked up trash. They sat on their front steps and chatted with neighbors. They had three times as many friends and twice as many acquaintances as the people on Franklin.
On Gough Street, residents said that the old feeling of community was disappearing as traffic increaseD. People were becoming more and more preoccupied with their own lives. A number of families had recently moved and more were considering. Those who were staying expressed deep regret at the destruction of their community.

What is the writer’s attitude toward heavy traffic when he mentions the Appleyard’s study?

A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic through an area affects people in the way that a sudden increase in crime does. Appleyard observed this by finding three blocks of houses in San Francisco that looked much alike and had the same kind of middle-class and working-class residents, with approximately the same ethnic mix. The difference was that only 2,000 cars a day ran down Octavia Street (LIGHT street, in Appleyard’s terminology) while Gough Street (MEDIUM street) was used by 8,000 cars daily, and Franklin Street (HEAVY street) had around 16,000 cars a day. Franklin Street often had as many cars in an hour as Octavia had in a day.
Heavy traffic brought with it danger, noise, fumes and soot, directly, and trash secondarily. That is, the cars didn’t bring in much trash, but when trash accumulated, residents seldom picked it up. The cars, Appleyard determined, reduced the amount of territory residents felt responsible for. Noise was a constant intrusion into their homes. Many Franklin Street residents covered their doors and windows and spent most of their time in the rear of their houses. Most families with children had already left.
Conditions on Octavia Street were much different. Residents picked up trash. They sat on their front steps and chatted with neighbors. They had three times as many friends and twice as many acquaintances as the people on Franklin.
On Gough Street, residents said that the old feeling of community was disappearing as traffic increaseD. People were becoming more and more preoccupied with their own lives. A number of families had recently moved and more were considering. Those who were staying expressed deep regret at the destruction of their community.

In what order does the author present detailed discussions of the three streets?

A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic through an area affects people in the way that a sudden increase in crime does. Appleyard observed this by finding three blocks of houses in San Francisco that looked much alike and had the same kind of middle-class and working-class residents, with approximately the same ethnic mix. The difference was that only 2,000 cars a day ran down Octavia Street (LIGHT street, in Appleyard’s terminology) while Gough Street (MEDIUM street) was used by 8,000 cars daily, and Franklin Street (HEAVY street) had around 16,000 cars a day. Franklin Street often had as many cars in an hour as Octavia had in a day.
Heavy traffic brought with it danger, noise, fumes and soot, directly, and trash secondarily. That is, the cars didn’t bring in much trash, but when trash accumulated, residents seldom picked it up. The cars, Appleyard determined, reduced the amount of territory residents felt responsible for. Noise was a constant intrusion into their homes. Many Franklin Street residents covered their doors and windows and spent most of their time in the rear of their houses. Most families with children had already left.
Conditions on Octavia Street were much different. Residents picked up trash. They sat on their front steps and chatted with neighbors. They had three times as many friends and twice as many acquaintances as the people on Franklin.
On Gough Street, residents said that the old feeling of community was disappearing as traffic increaseD. People were becoming more and more preoccupied with their own lives. A number of families had recently moved and more were considering. Those who were staying expressed deep regret at the destruction of their community.

In what order does the author present detailed discussions of the three streets?

A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic through an area affects people in the way that a sudden increase in crime does. Appleyard observed this by finding three blocks of houses in San Francisco that looked much alike and had the same kind of middle-class and working-class residents, with approximately the same ethnic mix. The difference was that only 2,000 cars a day ran down Octavia Street (LIGHT street, in Appleyard’s terminology) while Gough Street (MEDIUM street) was used by 8,000 cars daily, and Franklin Street (HEAVY street) had around 16,000 cars a day. Franklin Street often had as many cars in an hour as Octavia had in a day.
Heavy traffic brought with it danger, noise, fumes and soot, directly, and trash secondarily. That is, the cars didn’t bring in much trash, but when trash accumulated, residents seldom picked it up. The cars, Appleyard determined, reduced the amount of territory residents felt responsible for. Noise was a constant intrusion into their homes. Many Franklin Street residents covered their doors and windows and spent most of their time in the rear of their houses. Most families with children had already left.
Conditions on Octavia Street were much different. Residents picked up trash. They sat on their front steps and chatted with neighbors. They had three times as many friends and twice as many acquaintances as the people on Franklin.
On Gough Street, residents said that the old feeling of community was disappearing as traffic increaseD. People were becoming more and more preoccupied with their own lives. A number of families had recently moved and more were considering. Those who were staying expressed deep regret at the destruction of their community.

Which of the following is NOT a statement you would expect from a resident of Gough Street?

A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic through an area affects people in the way that a sudden increase in crime does. Appleyard observed this by finding three blocks of houses in San Francisco that looked much alike and had the same kind of middle-class and working-class residents, with approximately the same ethnic mix. The difference was that only 2,000 cars a day ran down Octavia Street (LIGHT street, in Appleyard’s terminology) while Gough Street (MEDIUM street) was used by 8,000 cars daily, and Franklin Street (HEAVY street) had around 16,000 cars a day. Franklin Street often had as many cars in an hour as Octavia had in a day.
Heavy traffic brought with it danger, noise, fumes and soot, directly, and trash secondarily. That is, the cars didn’t bring in much trash, but when trash accumulated, residents seldom picked it up. The cars, Appleyard determined, reduced the amount of territory residents felt responsible for. Noise was a constant intrusion into their homes. Many Franklin Street residents covered their doors and windows and spent most of their time in the rear of their houses. Most families with children had already left.
Conditions on Octavia Street were much different. Residents picked up trash. They sat on their front steps and chatted with neighbors. They had three times as many friends and twice as many acquaintances as the people on Franklin.
On Gough Street, residents said that the old feeling of community was disappearing as traffic increaseD. People were becoming more and more preoccupied with their own lives. A number of families had recently moved and more were considering. Those who were staying expressed deep regret at the destruction of their community.

The author’s main purpose in the second paragraph is to __________.

A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic through an area affects people in the way that a sudden increase in crime does. Appleyard observed this by finding three blocks of houses in San Francisco that looked much alike and had the same kind of middle-class and working-class residents, with approximately the same ethnic mix. The difference was that only 2,000 cars a day ran down Octavia Street (LIGHT street, in Appleyard’s terminology) while Gough Street (MEDIUM street) was used by 8,000 cars daily, and Franklin Street (HEAVY street) had around 16,000 cars a day. Franklin Street often had as many cars in an hour as Octavia had in a day.
Heavy traffic brought with it danger, noise, fumes and soot, directly, and trash secondarily. That is, the cars didn’t bring in much trash, but when trash accumulated, residents seldom picked it up. The cars, Appleyard determined, reduced the amount of territory residents felt responsible for. Noise was a constant intrusion into their homes. Many Franklin Street residents covered their doors and windows and spent most of their time in the rear of their houses. Most families with children had already left.
Conditions on Octavia Street were much different. Residents picked up trash. They sat on their front steps and chatted with neighbors. They had three times as many friends and twice as many acquaintances as the people on Franklin.
On Gough Street, residents said that the old feeling of community was disappearing as traffic increaseD. People were becoming more and more preoccupied with their own lives. A number of families had recently moved and more were considering. Those who were staying expressed deep regret at the destruction of their community.

All of the following are direct results of heavy traffic EXCEPT

A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic through an area affects people in the way that a sudden increase in crime does. Appleyard observed this by finding three blocks of houses in San Francisco that looked much alike and had the same kind of middle-class and working-class residents, with approximately the same ethnic mix. The difference was that only 2,000 cars a day ran down Octavia Street (LIGHT street, in Appleyard’s terminology) while Gough Street (MEDIUM street) was used by 8,000 cars daily, and Franklin Street (HEAVY street) had around 16,000 cars a day. Franklin Street often had as many cars in an hour as Octavia had in a day.
Heavy traffic brought with it danger, noise, fumes and soot, directly, and trash secondarily. That is, the cars didn’t bring in much trash, but when trash accumulated, residents seldom picked it up. The cars, Appleyard determined, reduced the amount of territory residents felt responsible for. Noise was a constant intrusion into their homes. Many Franklin Street residents covered their doors and windows and spent most of their time in the rear of their houses. Most families with children had already left.
Conditions on Octavia Street were much different. Residents picked up trash. They sat on their front steps and chatted with neighbors. They had three times as many friends and twice as many acquaintances as the people on Franklin.
On Gough Street, residents said that the old feeling of community was disappearing as traffic increaseD. People were becoming more and more preoccupied with their own lives. A number of families had recently moved and more were considering. Those who were staying expressed deep regret at the destruction of their community.

Approximately how many cars used Franklin Street daily?

A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic through an area affects people in the way that a sudden increase in crime does. Appleyard observed this by finding three blocks of houses in San Francisco that looked much alike and had the same kind of middle-class and working-class residents, with approximately the same ethnic mix. The difference was that only 2,000 cars a day ran down Octavia Street (LIGHT street, in Appleyard’s terminology) while Gough Street (MEDIUM street) was used by 8,000 cars daily, and Franklin Street (HEAVY street) had around 16,000 cars a day. Franklin Street often had as many cars in an hour as Octavia had in a day.
Heavy traffic brought with it danger, noise, fumes and soot, directly, and trash secondarily. That is, the cars didn’t bring in much trash, but when trash accumulated, residents seldom picked it up. The cars, Appleyard determined, reduced the amount of territory residents felt responsible for. Noise was a constant intrusion into their homes. Many Franklin Street residents covered their doors and windows and spent most of their time in the rear of their houses. Most families with children had already left.
Conditions on Octavia Street were much different. Residents picked up trash. They sat on their front steps and chatted with neighbors. They had three times as many friends and twice as many acquaintances as the people on Franklin.
On Gough Street, residents said that the old feeling of community was disappearing as traffic increaseD. People were becoming more and more preoccupied with their own lives. A number of families had recently moved and more were considering. Those who were staying expressed deep regret at the destruction of their community.

The three streets mentioned in this passage are different in that __________.

A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic through an area affects people in the way that a sudden increase in crime does. Appleyard observed this by finding three blocks of houses in San Francisco that looked much alike and had the same kind of middle-class and working-class residents, with approximately the same ethnic mix. The difference was that only 2,000 cars a day ran down Octavia Street (LIGHT street, in Appleyard’s terminology) while Gough Street (MEDIUM street) was used by 8,000 cars daily, and Franklin Street (HEAVY street) had around 16,000 cars a day. Franklin Street often had as many cars in an hour as Octavia had in a day.
    Heavy traffic brought with it danger, noise, fumes and soot, directly, and trash secondarily. That is, the cars didn’t bring in much trash, but when trash accumulated, residents seldom picked it up. The cars, Appleyard determined, reduced the amount of territory residents felt responsible for. Noise was a constant intrusion into their homes. Many Franklin Street residents covered their doors and windows and spent most of their time in the rear of their houses. Most families with children had already left.
    Conditions on Octavia Street were much different. Residents picked up trash. They sat on their front steps and chatted with neighbors. They had three times as many friends and twice as many acquaintances as the people on Franklin.
    On Gough Street, residents said that the old feeling of community was disappearing as traffic increaseD. People were becoming more and more preoccupied with their own lives. A number of families had recently moved and more were considering. Those who were staying expressed deep regret at the destruction of their community.

The word “astounding” in line 1 is closest in meaning to

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 
Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 
The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

According to the passage, the highest amount of pheromone vapor is found

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 
Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 
The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

The word “oscillating“ in line 11 is closest in meaning to' 

A falling         B: depositing         C: swinging         D: starting

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 
Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 
The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

According to the passage, how are ants guided by trail pheromones?' 

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 
Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 
The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

The author mentions the trail pheromone of the leafcutter ant in line 8 to point out

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 
Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 
The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

According to the passage, why do ants use different compounds as trail pheromones?

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 
Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 
The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

The phrase “the one” in line 5 refers to a single' 

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 
Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 
The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

The word “intermittently” in live 4 is closest in meaning to' 

Many ants forage across the countryside in large numbers and undertake mass migrations; these activities proceed because one ant lays a trail on the ground for the others to follow. As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail pheromone – a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction. 
Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use a wide variety of compounds as trail pheromones. Ants can be extremely sensitive to these signals. Investigators working with the trail pheromone of the leafcutter ant Atta texana calculated that one milligram of this substance would suffice to lead a column of ants three times around Earth. 
The vapor of the evaporating pheromone over the trail guides an ant along the way, and the ant detects this signal with receptors in its antennae. A trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called a vapor space. In following the trail, the ant moves to the right and left, oscillating from side to side across the line of the trail itself, bringing first one and then the other antenna into the vapor space. As the ant moves to the right, its left antenna arrives in the vapor space. The signal it receives causes it to swing to the left, and the ant then pursues this new course until its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail.

What does the passage mainly discuss?' 

Sunlight offers many ways to get energy. A window can allow warm sunlight into your room. Solar water-heating systems can use sunlight to warm the water for your home, swimming pool and school. Sunlight also warms the Earth and causes wind. Electricity can be made by wind generators. 
Photovoltaic, or PV system use a type of material that converts sunlight into electricity. PV systems can power your air conditioner or a satellite like the International Space Station. PV systems are also used to run a calculator, recharge cell phone, or even power lightweight cars. 
Sunlight is also changed into electricity by concentrating solar power or CSP systems. CSP systems have mirrors that focus the sunlight. The concentrated sunlight turns water into steam which turns a turbine that is connected to an electric generator. A CSP system usually uses sunlight to make steam. CSP power plants can store large amount of heat. The stored heat is used to make electricity at night. During cloud days, many CSP plants can also burn natural gas to provide the heat that is used to turn water into steam. 
Sunlight provides the energy needed to grow plants and make large amount of environmentally friendly heat and electricity. Solar energy can provide power today and for a long time in the future. 

In the fourth paragraph, the word “which” refers to _______ 

Sunlight offers many ways to get energy. A window can allow warm sunlight into your room. Solar water-heating systems can use sunlight to warm the water for your home, swimming pool and school. Sunlight also warms the Earth and causes wind. Electricity can be made by wind generators. 
Photovoltaic, or PV system use a type of material that converts sunlight into electricity. PV systems can power your air conditioner or a satellite like the International Space Station. PV systems are also used to run a calculator, recharge cell phone, or even power lightweight cars. 
Sunlight is also changed into electricity by concentrating solar power or CSP systems. CSP systems have mirrors that focus the sunlight. The concentrated sunlight turns water into steam which turns a turbine that is connected to an electric generator. A CSP system usually uses sunlight to make steam. CSP power plants can store large amount of heat. The stored heat is used to make electricity at night. During cloud days, many CSP plants can also burn natural gas to provide the heat that is used to turn water into steam. 
Sunlight provides the energy needed to grow plants and make large amount of environmentally friendly heat and electricity. Solar energy can provide power today and for a long time in the future. 

In the third paragraph, the word “convert” is closest in meaning to _______ 

Sunlight offers many ways to get energy. A window can allow warm sunlight into your room. Solar water-heating systems can use sunlight to warm the water for your home, swimming pool and school. Sunlight also warms the Earth and causes wind. Electricity can be made by wind generators. 
Photovoltaic, or PV system use a type of material that converts sunlight into electricity. PV systems can power your air conditioner or a satellite like the International Space Station. PV systems are also used to run a calculator, recharge cell phone, or even power lightweight cars. 
Sunlight is also changed into electricity by concentrating solar power or CSP systems. CSP systems have mirrors that focus the sunlight. The concentrated sunlight turns water into steam which turns a turbine that is connected to an electric generator. A CSP system usually uses sunlight to make steam. CSP power plants can store large amount of heat. The stored heat is used to make electricity at night. During cloud days, many CSP plants can also burn natural gas to provide the heat that is used to turn water into steam. 
Sunlight provides the energy needed to grow plants and make large amount of environmentally friendly heat and electricity. Solar energy can provide power today and for a long time in the future. 

Which of the following statements is NOT true? 

Sunlight offers many ways to get energy. A window can allow warm sunlight into your room. Solar water-heating systems can use sunlight to warm the water for your home, swimming pool and school. Sunlight also warms the Earth and causes wind. Electricity can be made by wind generators. 
Photovoltaic, or PV system use a type of material that converts sunlight into electricity. PV systems can power your air conditioner or a satellite like the International Space Station. PV systems are also used to run a calculator, recharge cell phone, or even power lightweight cars. 
Sunlight is also changed into electricity by concentrating solar power or CSP systems. CSP systems have mirrors that focus the sunlight. The concentrated sunlight turns water into steam which turns a turbine that is connected to an electric generator. A CSP system usually uses sunlight to make steam. CSP power plants can store large amount of heat. The stored heat is used to make electricity at night. During cloud days, many CSP plants can also burn natural gas to provide the heat that is used to turn water into steam. 
Sunlight provides the energy needed to grow plants and make large amount of environmentally friendly heat and electricity. Solar energy can provide power today and for a long time in the future. 

To help the readers understand some of the benefits of solar energy, the author ________ 

Sunlight offers many ways to get energy. A window can allow warm sunlight into your room. Solar water-heating systems can use sunlight to warm the water for your home, swimming pool and school. Sunlight also warms the Earth and causes wind. Electricity can be made by wind generators. 
Photovoltaic, or PV system use a type of material that converts sunlight into electricity. PV systems can power your air conditioner or a satellite like the International Space Station. PV systems are also used to run a calculator, recharge cell phone, or even power lightweight cars. 
Sunlight is also changed into electricity by concentrating solar power or CSP systems. CSP systems have mirrors that focus the sunlight. The concentrated sunlight turns water into steam which turns a turbine that is connected to an electric generator. A CSP system usually uses sunlight to make steam. CSP power plants can store large amount of heat. The stored heat is used to make electricity at night. During cloud days, many CSP plants can also burn natural gas to provide the heat that is used to turn water into steam. 
Sunlight provides the energy needed to grow plants and make large amount of environmentally friendly heat and electricity. Solar energy can provide power today and for a long time in the future. 

The drawback of nuclear fission is that ________ 

Sunlight offers many ways to get energy. A window can allow warm sunlight into your room. Solar water-heating systems can use sunlight to warm the water for your home, swimming pool and school. Sunlight also warms the Earth and causes wind. Electricity can be made by wind generators. 
Photovoltaic, or PV system use a type of material that converts sunlight into electricity. PV systems can power your air conditioner or a satellite like the International Space Station. PV systems are also used to run a calculator, recharge cell phone, or even power lightweight cars. 
Sunlight is also changed into electricity by concentrating solar power or CSP systems. CSP systems have mirrors that focus the sunlight. The concentrated sunlight turns water into steam which turns a turbine that is connected to an electric generator. A CSP system usually uses sunlight to make steam. CSP power plants can store large amount of heat. The stored heat is used to make electricity at night. During cloud days, many CSP plants can also burn natural gas to provide the heat that is used to turn water into steam. 
Sunlight provides the energy needed to grow plants and make large amount of environmentally friendly heat and electricity. Solar energy can provide power today and for a long time in the future. 

In the first paragraph, the word “fossil fuels” in line 2 means ________ 

Sunlight offers many ways to get energy. A window can allow warm sunlight into your room. Solar water-heating systems can use sunlight to warm the water for your home, swimming pool and school. Sunlight also warms the Earth and causes wind. Electricity can be made by wind generators. 
Photovoltaic, or PV system use a type of material that converts sunlight into electricity. PV systems can power your air conditioner or a satellite like the International Space Station. PV systems are also used to run a calculator, recharge cell phone, or even power lightweight cars. 
Sunlight is also changed into electricity by concentrating solar power or CSP systems. CSP systems have mirrors that focus the sunlight. The concentrated sunlight turns water into steam which turns a turbine that is connected to an electric generator. A CSP system usually uses sunlight to make steam. CSP power plants can store large amount of heat. The stored heat is used to make electricity at night. During cloud days, many CSP plants can also burn natural gas to provide the heat that is used to turn water into steam. 
Sunlight provides the energy needed to grow plants and make large amount of environmentally friendly heat and electricity. Solar energy can provide power today and for a long time in the future. 

This article is mainly about ______ 

The handling and delivery of mail has always been a serious business, underpinned by the trust of the public in requiring timeliness, safety, and confidentiality. After early beginnings using horseback and stagecoach, and although cars and trucks later replaced stagecoaches and wagons, the Railway Mail Service still stands as one of America’s most resourceful and exciting postal innovations. This service began in 1832, but grew slowly until the Civil War. Then from 1862, by sorting the mail on board moving trains, the Post Office Department was able to decentralize its operations as railroads began to crisscross the nation on a regular basis, and speed up mail delivery. This service lasted until 1974. During peak decades of service, railway mail clerks handled 93% of all non-local mail and by 1905 the service had over 12,000 employees. 
Railway Post Office trains used a system of mail cranes to exchange mail at stations without stopping. As a train approached the crane, a clerk prepared the catcher arm which would then snatch the incoming mailbag in the blink of an eye. The clerk then booted out the outgoing mailbag. Experienced clerks were considered the elite of the Postal Service’s employees, and spoke with pride of making the switch at night with nothing but the curves and feel of the track to warn them of an upcoming catch. They also worked under the greatest pressure and their jobs were considered to be exhausting and dangerous. In addition to regular demands of their jobs they could find themselves the victims of train wrecks and robberies. 
As successful as it was, “mail-on-the-fly” still had its share of glitches. If they hoisted the train’s catcher arm too soon, they risked hitting switch targets, telegraph poles or semaphores, which would rip the catcher arm off the train. Too late, and they would miss an exchange. 

The public expects the following three services in handling and delivery of mail except___________.

The handling and delivery of mail has always been a serious business, underpinned by the trust of the public in requiring timeliness, safety, and confidentiality. After early beginnings using horseback and stagecoach, and although cars and trucks later replaced stagecoaches and wagons, the Railway Mail Service still stands as one of America’s most resourceful and exciting postal innovations. This service began in 1832, but grew slowly until the Civil War. Then from 1862, by sorting the mail on board moving trains, the Post Office Department was able to decentralize its operations as railroads began to crisscross the nation on a regular basis, and speed up mail delivery. This service lasted until 1974. During peak decades of service, railway mail clerks handled 93% of all non-local mail and by 1905 the service had over 12,000 employees. 
Railway Post Office trains used a system of mail cranes to exchange mail at stations without stopping. As a train approached the crane, a clerk prepared the catcher arm which would then snatch the incoming mailbag in the blink of an eye. The clerk then booted out the outgoing mailbag. Experienced clerks were considered the elite of the Postal Service’s employees, and spoke with pride of making the switch at night with nothing but the curves and feel of the track to warn them of an upcoming catch. They also worked under the greatest pressure and their jobs were considered to be exhausting and dangerous. In addition to regular demands of their jobs they could find themselves the victims of train wrecks and robberies. 
As successful as it was, “mail-on-the-fly” still had its share of glitches. If they hoisted the train’s catcher arm too soon, they risked hitting switch targets, telegraph poles or semaphores, which would rip the catcher arm off the train. Too late, and they would miss an exchange. 

Which of the following is TRUE according to the passage?

The handling and delivery of mail has always been a serious business, underpinned by the trust of the public in requiring timeliness, safety, and confidentiality. After early beginnings using horseback and stagecoach, and although cars and trucks later replaced stagecoaches and wagons, the Railway Mail Service still stands as one of America’s most resourceful and exciting postal innovations. This service began in 1832, but grew slowly until the Civil War. Then from 1862, by sorting the mail on board moving trains, the Post Office Department was able to decentralize its operations as railroads began to crisscross the nation on a regular basis, and speed up mail delivery. This service lasted until 1974. During peak decades of service, railway mail clerks handled 93% of all non-local mail and by 1905 the service had over 12,000 employees. 
Railway Post Office trains used a system of mail cranes to exchange mail at stations without stopping. As a train approached the crane, a clerk prepared the catcher arm which would then snatch the incoming mailbag in the blink of an eye. The clerk then booted out the outgoing mailbag. Experienced clerks were considered the elite of the Postal Service’s employees, and spoke with pride of making the switch at night with nothing but the curves and feel of the track to warn them of an upcoming catch. They also worked under the greatest pressure and their jobs were considered to be exhausting and dangerous. In addition to regular demands of their jobs they could find themselves the victims of train wrecks and robberies. 
As successful as it was, “mail-on-the-fly” still had its share of glitches. If they hoisted the train’s catcher arm too soon, they risked hitting switch targets, telegraph poles or semaphores, which would rip the catcher arm off the train. Too late, and they would miss an exchange. 

The word “glitches” in the third paragraph can be replaced by________. ' 

The handling and delivery of mail has always been a serious business, underpinned by the trust of the public in requiring timeliness, safety, and confidentiality. After early beginnings using horseback and stagecoach, and although cars and trucks later replaced stagecoaches and wagons, the Railway Mail Service still stands as one of America’s most resourceful and exciting postal innovations. This service began in 1832, but grew slowly until the Civil War. Then from 1862, by sorting the mail on board moving trains, the Post Office Department was able to decentralize its operations as railroads began to crisscross the nation on a regular basis, and speed up mail delivery. This service lasted until 1974. During peak decades of service, railway mail clerks handled 93% of all non-local mail and by 1905 the service had over 12,000 employees. 
Railway Post Office trains used a system of mail cranes to exchange mail at stations without stopping. As a train approached the crane, a clerk prepared the catcher arm which would then snatch the incoming mailbag in the blink of an eye. The clerk then booted out the outgoing mailbag. Experienced clerks were considered the elite of the Postal Service’s employees, and spoke with pride of making the switch at night with nothing but the curves and feel of the track to warn them of an upcoming catch. They also worked under the greatest pressure and their jobs were considered to be exhausting and dangerous. In addition to regular demands of their jobs they could find themselves the victims of train wrecks and robberies. 
As successful as it was, “mail-on-the-fly” still had its share of glitches. If they hoisted the train’s catcher arm too soon, they risked hitting switch targets, telegraph poles or semaphores, which would rip the catcher arm off the train. Too late, and they would miss an exchange. 

According to the passage, the Railway Mail Service commenced in_________. ' 

The handling and delivery of mail has always been a serious business, underpinned by the trust of the public in requiring timeliness, safety, and confidentiality. After early beginnings using horseback and stagecoach, and although cars and trucks later replaced stagecoaches and wagons, the Railway Mail Service still stands as one of America’s most resourceful and exciting postal innovations. This service began in 1832, but grew slowly until the Civil War. Then from 1862, by sorting the mail on board moving trains, the Post Office Department was able to decentralize its operations as railroads began to crisscross the nation on a regular basis, and speed up mail delivery. This service lasted until 1974. During peak decades of service, railway mail clerks handled 93% of all non-local mail and by 1905 the service had over 12,000 employees. 
Railway Post Office trains used a system of mail cranes to exchange mail at stations without stopping. As a train approached the crane, a clerk prepared the catcher arm which would then snatch the incoming mailbag in the blink of an eye. The clerk then booted out the outgoing mailbag. Experienced clerks were considered the elite of the Postal Service’s employees, and spoke with pride of making the switch at night with nothing but the curves and feel of the track to warn them of an upcoming catch. They also worked under the greatest pressure and their jobs were considered to be exhausting and dangerous. In addition to regular demands of their jobs they could find themselves the victims of train wrecks and robberies. 
As successful as it was, “mail-on-the-fly” still had its share of glitches. If they hoisted the train’s catcher arm too soon, they risked hitting switch targets, telegraph poles or semaphores, which would rip the catcher arm off the train. Too late, and they would miss an exchange. 

What does the passage mainly discuss? 

The handling and delivery of mail has always been a serious business, underpinned by the trust of the public in requiring timeliness, safety, and confidentiality. After early beginnings using horseback and stagecoach, and although cars and trucks later replaced stagecoaches and wagons, the Railway Mail Service still stands as one of America’s most resourceful and exciting postal innovations. This service began in 1832, but grew slowly until the Civil War. Then from 1862, by sorting the mail on board moving trains, the Post Office Department was able to decentralize its operations as railroads began to crisscross the nation on a regular basis, and speed up mail delivery. This service lasted until 1974. During peak decades of service, railway mail clerks handled 93% of all non-local mail and by 1905 the service had over 12,000 employees. 
Railway Post Office trains used a system of mail cranes to exchange mail at stations without stopping. As a train approached the crane, a clerk prepared the catcher arm which would then snatch the incoming mailbag in the blink of an eye. The clerk then booted out the outgoing mailbag. Experienced clerks were considered the elite of the Postal Service’s employees, and spoke with pride of making the switch at night with nothing but the curves and feel of the track to warn them of an upcoming catch. They also worked under the greatest pressure and their jobs were considered to be exhausting and dangerous. In addition to regular demands of their jobs they could find themselves the victims of train wrecks and robberies. 
As successful as it was, “mail-on-the-fly” still had its share of glitches. If they hoisted the train’s catcher arm too soon, they risked hitting switch targets, telegraph poles or semaphores, which would rip the catcher arm off the train. Too late, and they would miss an exchange. 

The word “elite” in the second paragraph is closest in meaning to___________. 

The handling and delivery of mail has always been a serious business, underpinned by the trust of the public in requiring timeliness, safety, and confidentiality. After early beginnings using horseback and stagecoach, and although cars and trucks later replaced stagecoaches and wagons, the Railway Mail Service still stands as one of America’s most resourceful and exciting postal innovations. This service began in 1832, but grew slowly until the Civil War. Then from 1862, by sorting the mail on board moving trains, the Post Office Department was able to decentralize its operations as railroads began to crisscross the nation on a regular basis, and speed up mail delivery. This service lasted until 1974. During peak decades of service, railway mail clerks handled 93% of all non-local mail and by 1905 the service had over 12,000 employees. 
Railway Post Office trains used a system of mail cranes to exchange mail at stations without stopping. As a train approached the crane, a clerk prepared the catcher arm which would then snatch the incoming mailbag in the blink of an eye. The clerk then booted out the outgoing mailbag. Experienced clerks were considered the elite of the Postal Service’s employees, and spoke with pride of making the switch at night with nothing but the curves and feel of the track to warn them of an upcoming catch. They also worked under the greatest pressure and their jobs were considered to be exhausting and dangerous. In addition to regular demands of their jobs they could find themselves the victims of train wrecks and robberies. 
As successful as it was, “mail-on-the-fly” still had its share of glitches. If they hoisted the train’s catcher arm too soon, they risked hitting switch targets, telegraph poles or semaphores, which would rip the catcher arm off the train. Too late, and they would miss an exchange. 

Which of the following can be inferred from the first paragraph? 

Stars have been significant features in the design of many United States coins and their number has varied from one to forty-eight stars. Most of the coins issued from about 1799 to the early years of the twentieth century bore thirteen stars representing the thirteen original colonies. Curiously enough, the first American silver coins, issued in 1794, had fifteen stars because by that time Vermont and Kentucky has joined the Union. At that time it was apparently the intention of mint officials to add a star for each new state. Following the admission of Tennessee in 1796, for example, some varieties of half dimes, dimes, and half-dollars were produced with sixteen starts. As more states were admitted to the Union, however, it quickly became apparent that this scheme would not prove practical and the coins from A798 on were issued with only thirteen stars-one for each ofthe original colonies. Due to an error at the mint, one variety of the A828 half cent was issued with only twelve stars. There is also a variety of the large cent with only A2 stars, but this is the result of a die breakand is not a true error.

Why was a coin produced in 1828 with only twelve stars? 

Stars have been significant features in the design of many United States coins and their number has varied from one to forty-eight stars. Most of the coins issued from about 1799 to the early years of the twentieth century bore thirteen stars representing the thirteen original colonies. Curiously enough, the first American silver coins, issued in 1794, had fifteen stars because by that time Vermont and Kentucky has joined the Union. At that time it was apparently the intention of mint officials to add a star for each new state. Following the admission of Tennessee in 1796, for example, some varieties of half dimes, dimes, and half-dollars were produced with sixteen starts. As more states were admitted to the Union, however, it quickly became apparent that this scheme would not prove practical and the coins from A798 on were issued with only thirteen stars-one for each ofthe original colonies. Due to an error at the mint, one variety of the A828 half cent was issued with only twelve stars. There is also a variety of the large cent with only A2 stars, but this is the result of a die breakand is not a true error.

Which of the following can be inferred about the order in which Kentucky, Tennessee, and Vermont joined the Union?

Stars have been significant features in the design of many United States coins and their number has varied from one to forty-eight stars. Most of the coins issued from about 1799 to the early years of the twentieth century bore thirteen stars representing the thirteen original colonies. Curiously enough, the first American silver coins, issued in 1794, had fifteen stars because by that time Vermont and Kentucky has joined the Union. At that time it was apparently the intention of mint officials to add a star for each new state. Following the admission of Tennessee in 1796, for example, some varieties of half dimes, dimes, and half-dollars were produced with sixteen starts. As more states were admitted to the Union, however, it quickly became apparent that this scheme would not prove practical and the coins from A798 on were issued with only thirteen stars-one for each ofthe original colonies. Due to an error at the mint, one variety of the A828 half cent was issued with only twelve stars. There is also a variety of the large cent with only A2 stars, but this is the result of a die breakand is not a true error.

The expression “Curiously enough” is used because the author finds it strange that _______ .

Stars have been significant features in the design of many United States coins and their number has varied from one to forty-eight stars. Most of the coins issued from about 1799 to the early years of the twentieth century bore thirteen stars representing the thirteen original colonies. Curiously enough, the first American silver coins, issued in 1794, had fifteen stars because by that time Vermont and Kentucky has joined the Union. At that time it was apparently the intention of mint officials to add a star for each new state. Following the admission of Tennessee in 1796, for example, some varieties of half dimes, dimes, and half-dollars were produced with sixteen starts. As more states were admitted to the Union, however, it quickly became apparent that this scheme would not prove practical and the coins from A798 on were issued with only thirteen stars-one for each ofthe original colonies. Due to an error at the mint, one variety of the A828 half cent was issued with only twelve stars. There is also a variety of the large cent with only A2 stars, but this is the result of a die breakand is not a true error.

The word “bore” in line 2 is closest in meaning to ________ .

Stars have been significant features in the design of many United States coins and their number has varied from one to forty-eight stars. Most of the coins issued from about 1799 to the early years of the twentieth century bore thirteen stars representing the thirteen original colonies. Curiously enough, the first American silver coins, issued in 1794, had fifteen stars because by that time Vermont and Kentucky has joined the Union. At that time it was apparently the intention of mint officials to add a star for each new state. Following the admission of Tennessee in 1796, for example, some varieties of half dimes, dimes, and half-dollars were produced with sixteen starts. As more states were admitted to the Union, however, it quickly became apparent that this scheme would not prove practical and the coins from A798 on were issued with only thirteen stars-one for each ofthe original colonies. Due to an error at the mint, one variety of the A828 half cent was issued with only twelve stars. There is also a variety of the large cent with only A2 stars, but this is the result of a die breakand is not a true error.

The word “their” in line 1 refers to _______.

Stars have been significant features in the design of many United States coins and their number has varied from one to forty-eight stars. Most of the coins issued from about 1799 to the early years of the twentieth century bore thirteen stars representing the thirteen original colonies. Curiously enough, the first American silver coins, issued in 1794, had fifteen stars because by that time Vermont and Kentucky has joined the Union. At that time it was apparently the intention of mint officials to add a star for each new state. Following the admission of Tennessee in 1796, for example, some varieties of half dimes, dimes, and half-dollars were produced with sixteen starts. As more states were admitted to the Union, however, it quickly became apparent that this scheme would not prove practical and the coins from A798 on were issued with only thirteen stars-one for each ofthe original colonies. Due to an error at the mint, one variety of the A828 half cent was issued with only twelve stars. There is also a variety of the large cent with only A2 stars, but this is the result of a die breakand is not a true error.

What is the main topic of the passage?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

   Over the past 600 years, English has grown from a language of few speakers to become the dominant language of international communication. English as we know it today emerged around 1350, after having incorporated many elements of French that were introduced following the Norman invasion of 1066. Until the 1600s, English was, for the most part, spoken only in England and had not extended even as far as two centuries, English began to spread around the globe as a result of exploration, trade (including slave trade), colonization, and missionary work. Thus, small enclaves of English speakers became established and grew in various parts of the world. As these communities proliferated, English gradually became the primary language of international business, banking and diplomacy.

   Currently, about 80 percent of the information stored on computer systems worldwide is English. Two thirds of the world’s science writing is in English, and English is the main language of technology, advertising, media, international airports, and air traffic controllers. Today there are more than 700 million English users in the world, and over half of these are nonnative speakers, constituting the largest number of non-native users than any other language in the world..

According to the passage, approximately how many non-native users of English are there in the world today?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

   Over the past 600 years, English has grown from a language of few speakers to become the dominant language of international communication. English as we know it today emerged around 1350, after having incorporated many elements of French that were introduced following the Norman invasion of 1066. Until the 1600s, English was, for the most part, spoken only in England and had not extended even as far as two centuries, English began to spread around the globe as a result of exploration, trade (including slave trade), colonization, and missionary work. Thus, small enclaves of English speakers became established and grew in various parts of the world. As these communities proliferated, English gradually became the primary language of international business, banking and diplomacy.

   Currently, about 80 percent of the information stored on computer systems worldwide is English. Two thirds of the world’s science writing is in English, and English is the main language of technology, advertising, media, international airports, and air traffic controllers. Today there are more than 700 million English users in the world, and over half of these are nonnative speakers, constituting the largest number of non-native users than any other language in the world..

In the second paragraph, the word “stored” is closest in meaning to _________.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

   Over the past 600 years, English has grown from a language of few speakers to become the dominant language of international communication. English as we know it today emerged around 1350, after having incorporated many elements of French that were introduced following the Norman invasion of 1066. Until the 1600s, English was, for the most part, spoken only in England and had not extended even as far as two centuries, English began to spread around the globe as a result of exploration, trade (including slave trade), colonization, and missionary work. Thus, small enclaves of English speakers became established and grew in various parts of the world. As these communities proliferated, English gradually became the primary language of international business, banking and diplomacy.

   Currently, about 80 percent of the information stored on computer systems worldwide is English. Two thirds of the world’s science writing is in English, and English is the main language of technology, advertising, media, international airports, and air traffic controllers. Today there are more than 700 million English users in the world, and over half of these are nonnative speakers, constituting the largest number of non-native users than any other language in the world..

According to the passage, all of the following contributed to the spread of English around the world _________ .

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

   Over the past 600 years, English has grown from a language of few speakers to become the dominant language of international communication. English as we know it today emerged around 1350, after having incorporated many elements of French that were introduced following the Norman invasion of 1066. Until the 1600s, English was, for the most part, spoken only in England and had not extended even as far as two centuries, English began to spread around the globe as a result of exploration, trade (including slave trade), colonization, and missionary work. Thus, small enclaves of English speakers became established and grew in various parts of the world. As these communities proliferated, English gradually became the primary language of international business, banking and diplomacy.

   Currently, about 80 percent of the information stored on computer systems worldwide is English. Two thirds of the world’s science writing is in English, and English is the main language of technology, advertising, media, international airports, and air traffic controllers. Today there are more than 700 million English users in the world, and over half of these are nonnative speakers, constituting the largest number of non-native users than any other language in the world..

Approximately when did English begin to be used beyond England?