教材背景链接 交通 阻塞已经成为各 大城市最头疼的问题，在解决这个问题的过程中，世 界知名城 市都在各显神通，效果如何呢？让我们一起去领略一番吧！ You may ride on your bicycle in a rush to get to school every morning. You may fight to get a bit of space on a bus or on the subway.You may also watch taxis crawl(缓慢行进) their way through traffic jams.

Unit 9　Wheels