Each year there is an increasing number of cars on roads and street are millions of new cars are produced. One out of every six Americans works at putting together the parts of cars, driving trucks, building roads of filling cars with gas. Americans won’t live without cars!
Most Americans find it hard to think what life would be without a car. However some have realized the serious problem of air pollution by cars. The polluted air is poisonous(有毒的) and dangerous to health.
One way to get rid of(排除)the polluted air is to build a new kind of car. That’s what several of the large car factories are trying to do. But to build a clean car is easier said than done. Progress in this field has been slow.
Another way is to take the place of the car engine(发动机) by something else. Engineers are now working on some new cars. Many makers believe that it will take years to develop a practical model that pleases man.
To prevent the world from being polluted by cars, we’ll have to make some change in the way many of us live. Americans, for example, have to cut down on the number of their cars. They are encouraged to travel and go to work by bike. Riding a bike is thought to help keep the air clean.
But this change does not come easily — a large number of workers may find themselves without jobs if a car factory closed down. And the problem of air pollution would become less important than that of unemployment(失业).
Although cars have brought us a better life, they have also brought us new problems.
The writer wants to tell us that ______.

A:riding a bike is the only way out B:the number of cars must be cut down C:man won’t live without cars D:cars bring us not only a better life but also serious problems

The atmosphere and oceans are not the only parts of the environment being damaged. Rain forests are being quickly destroyed as well, and their survival is questionable. E. O. Wilson, a biologist at Harvard, calls the depletion(枯竭、耗尽)of rain forest areas "the greatest extinction since the end of the age of dinosaurs(恐龙)."
Unlike some environmental issues, rain forests’ depletion has fortunately received significant public and media’s attention. Despite the opposition to the cutting down of rain forests, the problem continues. Every year, Brazil chops down an area of forests the size of the state of Nebraska. In addition to the Amazon’s rain forests, many other forests are being cut down as well.: In Indonesia, Zaire, Papua-new Guinea, Malaysia, Burme, the Philippines, Peru, Colombia, Bolivia, and Venezuela, rain forests that were once great have been lost.
According to some estimates, 50 million acres of rain forest are cut down every year. The United Nations says the figure is closer to 17 million acres. The World Wildlife Fund says that every minute,25 to 50 acres are cut down or burnt to the ground.
The world’s growing population has been a primary reason of rain forests’ destruction. More people need land to live on and wood products to consume. Limiting population growth may be the first in a series of steps that would alleviate the destruction of the rain forests.
The words "chop down" in the second paragraph means______

A:clear B:make room for C:destroy D:cut down

Passage Four
The atmosphere and oceans are not the only parts of the environment being damaged. Rain forests are being quickly destroyed as well, and their survival is questionable. E. O. Wilson, a biologist at Harvard, calls the depletion(枯竭、耗尽)of rain forest areas "the greatest extinction since the end of the age of dinosaurs (恐龙)"
Unlike some environmental issues, rain forest depletion has fortunately received significant public and media attention. Despite the opposition to the cutting down of rain forests, the problem continues. Every year, Brazil chops down on area of forest the size of the state of Nebraska. In addition to the Amazon’s rain forests, many other forests are being cut down as well. In Indonesia, Zaire, Papua New Guinea, Malaysia, Burme, the Philippines peru, Colombia, Bolivia, and Venezuela, rain forests that were once great have been lost.
According to some estimates, 50 million acres of rain forest are cut down every year. The United Nations says the figure is closer to 17 million acres. The World Wildlife Fund says that every minute, 25 to 50 acres are cut or burned to the ground.
The world’s growing population has been a primary reason of rain forest destruction. More people need land to live on and wood products to consume. Limiting population growth may be the first in a series of steps that would limit the destruction of the rain forests.

The word "chop down" in the second paragraph means （）

A:clear B:make rooms for C:destroy D:cut down

The atmosphere and oceans are not the only parts of the environment being damaged. Rain forests are being quickly destroyed as well, and their survival is questionable. E. O. Wilson, a biologist at Harvard, calls the depletion(枯竭、耗尽)of rain forest areas "the greatest extinction since the end of the age of dinosaurs(恐龙)."
Unlike some environmental issues, rain forests’ depletion has fortunately received significant public and media’s attention. Despite the opposition to the cutting down of rain forests, the problem continues. Every year, Brazil chops down an area of forests the size of the state of Nebraska. In addition to the Amazon’s rain forests, many other forests are being cut down as well.: In Indonesia, Zaire, Papua-new Guinea, Malaysia, Burme, the Philippines, Peru, Colombia, Bolivia, and Venezuela, rain forests that were once great have been lost.
According to some estimates, 50 million acres of rain forest are cut down every year. The United Nations says the figure is closer to 17 million acres. The World Wildlife Fund says that every minute,25 to 50 acres are cut down or burnt to the ground.
The world’s growing population has been a primary reason of rain forests’ destruction. More people need land to live on and wood products to consume. Limiting population growth may be the first in a series of steps that would alleviate the destruction of the rain forests.

The words "chop down" in the second paragraph means（　）

A:clear B:make room for C:destroy D:cut down

Don't try to interrupt while others are talking.

A:cut down B:cut in C:cut up D:cut off

Each year there is an increasing number of cars on roads and street are millions of new cars are produced. One out of every six Americans works at putting together the parts of cars, driving trucks, building roads of filling cars with gas. Americans won’t live without cars!
Most Americans find it hard to think what life would be without a car. However some have realized the serious problem of air pollution by cars. The polluted air is poisonous(有毒的) and dangerous to health.
One way to get rid of(排除)the polluted air is to build a new kind of car. That’s what several of the large car factories are trying to do. But to build a clean car is easier said than done. Progress in this field has been slow.
Another way is to take the place of the car engine(发动机) by something else. Engineers are now working on some new cars. Many makers believe that it will take years to develop a practical model that pleases man.
To prevent the world from being polluted by cars, we’ll have to make some change in the way many of us live. Americans, for example, have to cut down on the number of their cars. They are encouraged to travel and go to work by bike. Riding a bike is thought to help keep the air clean.
But this change does not come easily — a large number of workers may find themselves without jobs if a car factory closed down. And the problem of air pollution would become less important than that of unemployment(失业).
Although cars have brought us a better life, they have also brought us new problems.
The writer wants to tell us that ______.

A:riding a bike is the only way out B:the number of cars must be cut down C:man won’t live without cars D:cars bring us not only a better life but also serious problems

Each year there is an increasing number of cars on roads and street are millions of new cars are produced. One out of every six Americans works at putting together the parts of cars, driving trucks, building roads of filling cars with gas. Americans won’t live without cars!
Most Americans find it hard to think what life would be without a car. However some have realized the serious problem of air pollution by cars. The polluted air is poisonous(有毒的) and dangerous to health.
One way to get rid of(排除)the polluted air is to build a new kind of car. That’s what several of the large car factories are trying to do. But to build a clean car is easier said than done. Progress in this field has been slow.
Another way is to take the place of the car engine(发动机) by something else. Engineers are now working on some new cars. Many makers believe that it will take years to develop a practical model that pleases man.
To prevent the world from being polluted by cars, we’ll have to make some change in the way many of us live. Americans, for example, have to cut down on the number of their cars. They are encouraged to travel and go to work by bike. Riding a bike is thought to help keep the air clean.
But this change does not come easily — a large number of workers may find themselves without jobs if a car factory closed down. And the problem of air pollution would become less important than that of unemployment(失业).
Although cars have brought us a better life, they have also brought us new problems.
The writer wants to tell us that ______.

A:riding a bike is the only way out B:the number of cars must be cut down C:man won’t live without cars D:cars bring us not only a better life but also serious problems