Modern life is impossible without travelling. The fastest way to travel is by air. With a modern plane you can travel in one day to places which took a month or more one hundred years ago.
Travelling by train is slower than by air, but it has its advantages. You can see the country you are travelling in. Modern trains have comfortable seats and dining cars. They make even the longest journey enjoyable.
Some people prefer to travel by sea when it is possible. There are large lines and river boats with which you can visit many other countries and different places. Travelling by sea is a very pleasant way to spend a holiday.
Many people like to travel by car. You can make your own timetable. You can travel three or four hundred miles or only fifty miles a day, just as you like. You can stop wherever you wish: where there is something interesting to see, at a good restaurant where you can enjoy a good meal, or a hotel to spend the night. That is why travelling by car is popular for pleasure trips, while people usually take a train or a plane when they are travelling on business.
21. From the passage we know that the most flexible(灵活的) way to travel is _________.
A. by car B. by train C. by plane D. by boat
22. The underlined word “They” in the passage refers to_________.
A. modern trains in the country B. the travelers on modern trains