阅读短文，根据短文内容，从短文后的五个选项中选出能填入空白处的最佳选项。选项中有一项为多余选项。（共8分，每小题2分）
The bicycle is one of the simplest yet most useful inventions in the world. What is the most surprising is that it was not invented easily, although the great inventor Leonardo da Vinci had drawn pictures for bicycles and flying machines and some other things. 小题1:_____________.
小题2:_______________, and there is no pollution at all. Even so, in most developed countries most people don’t go to work by bicycle. It is not because the bicycles are expensive or people feel tired if they ride to work. It’s because the number of cars on the roads becomes larger. 小题3:_____________. As a result, more people put their bicycles away and go to work in their cars. And in this way, the situation is made more serious. 小题4:
______________. 128
