综合阅读

　　From London to New York, from Hong Kong to Moscow, subways are an important way of transportation．Traffic in modern cities is often quite heavy, and it can sometimes take hours to cross a busy city in a car or bus．Subways help solve that problem, since they don't have to stop at traffic lights, and hundreds of people can take a subway train together．

　　In larger subway systems, such as Mexico City's, there are lines that go far beyond the city centre．In this way, people living in the suburbs can take a train to work．This reduces(减少)the traffic entering and leaving a city．It also helps reduce air pollution, a big problem in many cities．Finally, subways are usually cheaper．Basically, in a city with a subway, everybody wins!

根据短文内容，从A，B，C，D，E中选择最恰当的一项补全下列各句。

1．Subways around the world _________

2．Traffic in modern cities _________

3．In larger subway systems people living in the suburbs _________

4．Thousands of cars entering and leaving the city _________

5．Traveling by subway doesn't take a long time _________

A．increase(增加)air pollution(污染)．

B．can take the subway train to work．

C．are an important means of transportation．

D．because subways don't have to stop at traffic lights．

E．is often very heavy and it sometimes takes a long time to cross the city in a car or bus．