Cars are an important part of life in the United States. Without a car, most people feel that they are poor. And even if a person is poor he doesn’t feel really poor ___21___he has a car.Henry Ford was the man ____22____ first started making cars in large numbers. He probably didn’t know _____23_____ the car was going to change American culture. The car made the United States a nation on wheels. ____24_____ it helped make the United States what it is today.There are three main reasons the car became so ____25____ in the United States. ____26____, the country is a huge one and Americans like to move ____27____ it. The car provides the most comfortable and ____28____ form of transportation. ____29____ a car people can go to any place without spending a lot of money.The second reason cars are popular is the fact ____30_____the United States never really _____31____a practical and cheap public travel system. Long-distance trains have never been ____32___ common in the United States as they are ___33____ other parts of the world. Now there is a good system of air-service ____34____ by planes. But it is ____35____ expensive to be used frequently.The third reason is the most important one, though. The American spirit of independence is ____36_____ really made cars popular. Americans don’t like to wait ____37____a bus, or a train or even a plane. They don’t like to have to ____38____ an exact timetable. A car gives them the freedom to plan ___39____ time. And this is the freedom that Americans want ___40___ to have.本题为完形填空，有多选有单选__