Allan is visiting Beijing. He needs a mof the city. It shows how to travel around the city. Here are the ways of taround by bus. Buses go to dplaces in the city. They are cheap, but sometimes crowded. There are adouble-decker(双层) buses. They are comfortable(舒适) . You can go sight—seeing from the top deck. Here are two ways：One from the east to the west；another round the city like a ring road. The underground trains are fast, bvery crowded in the rush hours(在繁忙时间) . Taking taxis are fast, but they are rather e.