A、Convenient. B、Clean. C、Crowded. D、Lovely. C短文开头即提到在Tokyo，“我”想去的地方总是有太多的人，故C很好地概括了说话者对Tokyo的感觉。

Tokyo is one of those places that you can love and hate at the same time. In Tokyo there are always too many people in the places where I want to be. Of course there are too many cars. The Japanese drive very fast when they can. But in Tokyo they often spend a long time in traffic jams. Tokyo is not different when one wants to walk. At certain times of the day there are a lot of people on foot in London’s Oxford Street. But the streets near Ginza in Tokyo always have a lot of people on foot, and sometimes it is really difficult to walk. People are very polite; there are .just too many of them. The worst time to be in the street is at 11:30 at night. That is when the night-clubs are closing and everybody wants to go home. There are 35,000 night-clubs in Tokyo, and you do not often see one that is empty. Most people travel to and from work by train. Tokyo people buy six million train tickets every day. At most stations, trains arrive every two or three minutes, but at certain hours there do not seem to be enough trains. Although they are usually crowded, Japanese trains are very good. They always leave and arrive on time. On a London train you would see everybody reading a newspaper. In Tokyo trains everybody in a seat seems to be asleep, whether his journey is long or short.
20. How does the speaker feel about Tokyo?
21. Why is it difficult to walk in the streets near Ginza?
22. What do we learn about Japanese trains?