完形填空 The earth is our home. We must take good care of it. Life today is easier than it was hundreds of years ago, but it has brought some new （1） . One of the biggest problem is pollution. 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 （3） because there were not so many people. When the （4） was used up or the river was not clean in a place, man went to another place. However, man is （5） polluting the whole world nowadays. Air pollution is still the most serious pollution. It's bad for living things in the world. Many countries don't let people （6） anything bad in the houses and factories in the city. Pollution brought by SO2 is now the most dangerous kind of （7） pollution. It's mainly caused by heavy traffic. People say riding bikes is the （8） way to protect the environment in terms of means of transportation. Riding causes no pollution. But even in developed countries, most people don't go to work by bike. It's not because bikes are expensive or people would become tired if they ride to work. It's because the number of cars on the roads becomes larger. More and more people （9） their bikes and go to work by car and then things get worse and worse. There should be special roads only for bikes, making it so difficult and expensive for drivers to drive their cars in the city that they will go back to （10） their bikes.（1）A．matterB．questionsC．troublesD．problems（2）A．moonB．starC．earthD．sun（3）A．hardB．clearC．seriousD．big（4）A．landB．treeC．foodD．fruit（5）A．sadlyB．proudlyC．slowlyD．easily（6）A．burnB．createC．cookD．fire（7）A．waterB．whiteC．airD．noise（8）A．leastB．bestC．mostD．worst（9）A．put onB．put offC．put awayD．put up（10）A．useB．buyC．sellD．repair