The earth is our home. We must take care of it. Life today is easier than it was ____1____ years ago, but it has brought some new problems. One of the biggest problems is pollution（污染）. We can see it, smell it, drink it and even hear it.

　　Man has polluted the ____2____. The more people, the more pollution. Many years ago, the problem was not so serious because there were not so ____3____ people. When the land was used up（用光）or the river was not clean in a place, man went to ____4____ place. Now man is slowly polluting the whole world.

　　Many countries don't let people burn（燃烧）____7____ for air in houses and factories in the city. Pollution by is now the most dangerous kind of air pollution. It's caused by（由……引起）heavy traffic．People say it's ____8____ to ride bikes. When you are riding, there is not pollution. But even in developed countries, most people don't go to work by bike. It's not because bikes are expensive or people are tired ff they ride to work. It's because the number of cars on the roads becomes larger. So more people ____9____ their bikes and go to work by ear, then things are getting worse and worse. We should have special（特别的）roads only for bikes and make it ____10____ difficult and expensive for drivers to take their ears into the city that they will go back to using their bikes.

Traveling to work by car gets more expensive today. People can do nothing about the world’s price of petrol(汽油). They have to work, so that they can pay. However, some people are trying to stop driving to work..

　 People have found out that it is a good idea to ride a bike to work. More and more people return to bikes.

　 Children often go tot school by bike. But now businessmen are going to work by bike, too. “The bike is easy to use,” says Molly, “and it is also very cheap. It is a good way for those who do business like me. You can buy thirty bikes at the price of a small car. A bike doesn’t use expensive petrol. A 10-year-old child can learn to use a bike. And most bikes can be used for a long time.”

　 Mr Brown goes to his hospital by bike every day. He says, “A bike doesn’t cost a lot of money, and most families can have two or more ones. Bike-riding is good for our health. Today most people get fat because they don’t get enough exercise. So I tell my patients(病人) to buy bikes. In addition, in big cities it’s usually quicker to travel by bike than by bus or by car. Drivers can’t do anything but get angry when there is a traffic jam.(交通堵塞).”

11. Some people don’t want to drive to work because _______________.

　 A. the cares are getting expensive　　　　 B. the petrol is getting expensive

　 C. the care are difficult to take care of　　 D. petrol is hard to buy

12. In the second paragraph(段落), “return to bikes” means ____________.

　 A. begin to ride bikes again　　　　　 B. give bikes back to others

　 C. go back by bike　　　　　　　　 D. borrow bike from others

13. After reading, we know that Molly is a _____________.

　 A. doctor　　　　 B. student　　　　 C. patient　　　　　 D. businesswoman

14. Mr Brow thinks that bike-riding has _________ good points.

　 A. two　　 B. three　　　 C. four　　　　 D. five

15. This passage tells us about _________________.

　 A. cars and petrol　 B. expensive petrol　

C. back to bike time　 D. bike-riding for a long life