题目内容：

阅读短文,补充所缺单词。每个空只能填写一个形式正确、意义相符的单词。

Our cities are crowded. Now cities are1.of cars. Something will have to be done to change  2.. What will the cars of tomorrow be 3. ? Little cars may some day4.the place of today’s big cars. If everyone drives little cars in the future, there will be less 5.in the air. We can breathe clean and fresh air. There will also be more space6.parking cars in cities, and 7.streets will be less crowded. The space for ausual car 8.we use today is enough for three little cars. The little cars will cost much less to own and be safer to  9..What is10., these little cars can go about 65 kilometers per hour.