City traffic is a big problem in some cities in the world, especially in big cities. To solve the problem, someone are in favor of developing buses as means of city traffic.

　　Others are in favor of the subway train. Between them,which is the better choice? It is easier to take buses as means of city traffic than the subway trains because buses don't need special roads. But buses have also many disadvantages, some of which are very serious. They may cause louder noise and more traffic accidents. Buses give rise to serious air pollution and traffic jam. In order to stop what buses cause, a large amount of hand must be used to widen the roads.

　　On the contrary, the subway train is of more advantages. Except the difficulty and high cost of building the subway, it is superior to the buses in many aspects. Taking the advantages and disadvantages together into consideration, I would be in favor of developing the subway train as soon as possible.