the subway 地铁

　　These years you can see many underground railways are being built in some big cities. underground railway is both convenient and fast. the underground railway is also called “the subway‘.

　　There‘re lifts for you to go up or down. the trains‘ doors open and close automatically. in shanghai, during rush hours the underground arrives at the station every two minutes.

　　But with too many people taking the underground, people find it really too crowded. maybe shanghai needs more underground railways.
翻译：

这些年在一些大城市你可以看到许多地下铁路正在兴建。地下铁路既方便又快速。地下铁路也被称为“地铁”。

这有电梯供你上下。列车门自动打开和关闭。在上海，繁忙时间下每2分钟就有一列地铁到达。

但随着越来越多的人乘地铁，人们发现它太拥挤。也许上海需要更多的地铁。