comfortable and cheapest from of transportation. With a car people can go to any place without spending a lot of money.

　　The second reason that cars are popular is the fact that the United States never really developed an efficient and inexpensive from of public transportation. Long distance trains have never been as common in the United States as they are in the other parts of the world. Nowadays there is good system of air service provided by planes. But it is too expensive to be used frequently.

　　The third reason is the most important one. The American spirit of independence is what really made cars popular. Americans don't like to wait for a bus, or a train or even a plane. They don't like to have to follow an exact schedule. A car gives them the freedom to plan their own time. And this is the freedom that Americans want most to have.

　　The gas shortage has caused a big problem for Americans. But the answer will not be a bigger system of public transportation. The real solution will have to be a new kind of car, one that does not use so much gas.

6.Most Americans feel they are poor when they ______

　A.are out of work B.don't have enough food

　C .have no cars D.have no money

7..Henry was the first to ______ cars.

　A.find out B. produce C.sell D. find

8."a nation on wheels" means ______

　A.the nation is producing the best cars in the world

　B.everyone in this country owns a car

　C.there are more cars than trains in the country

　D. cars play a very important role in people's life

9.With a car people can go ______ easily.

　A. where B.to any place C.to anywhere D.any place

10.The real solution to the gas shortage problem is ______

　A.to make less cars B.to develop train service

　C.to develop a good transportation system D.to make gas-saving cars

C

People have smoked cigarettes for a long time now. The tobacco used to make cigarettes was grown in what is now part of the United States. Christopher Columbus, who discovered America, saw the Indians smoking, and soon the dried leaves were transported (运输) to Europe where smoking began to catch on. In the late 1800s, the Turks (土耳其人) made cigarettes popular.

Cigarettes smoke contains at least two harmful substances (物质), tar and nicotine, Tar, which forms as the tobacco bums, damages the lungs and therefore affects breathing. Nicotine, which is found in the leaves, causes the heart to beat faster and increases breathing rate (频率).

Smoking cigarettes is dangerous. The U.S. Public Health Service stated that cigarette smoking is the cause of lung cancers and several other deadly diseases. The U.S. government now requires that each package of cigarettes bear (带有) a special warning about the danger of smoking.

11. The expression "catch on" in the passage may mean ______.

A. start B. cost a lot

C. dangerous D. become popular

12. Before Columbus discovered America ______.