Unit 9　Wheels
　　【美文阅读】　
　　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 their way through traffic jams.
　　No matter where you are，all big cities around the world have traffic jams these days.But although they all have their problems，many cities also have a type of transport that has become a cultural icon(文化标识)．
　　In London，to avoid the traffic above ground，people use the"underground"，also called the"Tube"．The city has the oldest and most complicated underground railway system in the world and is the pride of many Londoners.With 12 lines and 275 stations across the city，the Tube，is normally the quickest and easiest way of getting around London.In London，you are never far from a Tube station.
　　New York is famous for its Yellow cabs.They serve as a quick and easy way of getting across Manhattan，w