Cars are too expensive for many people around the world to own．Now only that, many cities are 1 full of traffic, and many country areas have 2 roads．
So how people 3 those distances that are too 4 to walk? They 5 public transportation．If you ride the subway 6 the bus where you live, you can appreciate some of the 7 of public transportation．With many people 8 one bus or train, there is less traffic and, more importantly, less 9 ．
Which of the types of mass transit(运输)described below are you familiar with? If a regular bus can 10 dozens of people, imagine what a bus twice the size can hold! In Great Britain, there are many buses that are 11 double-deckers．
Buses in Haiti are often very crowded．It’s not 12 for passengers to actually sit on the 13 ．Buses are tenderly(温和地)called “tap-taps”, because the riders on the roof 14 when they want to be dropped off．
Many large cities around the world take advantage of the 15 beneath the streets and run underground trains．People in Paris, Mexico City, and Tokyo may use the subway system to go to school, to work, or to visit friends in other neighborhoods． 16 Japanese and French have 17 high-speed trains to link 18 cities．While electric trains in North America 19 130 kph, the French TGV(high-speed train)is the world’s 20 , averaging over 270 kph!