In Britain, cars, buses and bikes must keep to the left side of the street. If a person wants to cross a street, he must be very careful. Before he crosses a street, he has to stop and look to the right first and then the left. While in China, we look to the left instead:When visitors are in London;they should learn how to take buses and subways. The most important of all, they must know in which direction（方向 ）they are going and which bus and which subway they should take. At the bus stop they should wait for their buses to come. As soon as they get on a bus, they must pay for their tickets（票）.
