第一节 单项填空（共15小题，每小题1分；满分15分）
从A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
21.——I’m very tired. I can’t walk any farther, Jenny.
——________ Tom, you can do it!
A. No problem B. No hurry. C. Come on. D. That’s OK.
22. ______ number of books have been given to the library. And _____ number of the books is about 50,000.
A. A, a B. The, a C. A, the D. The, the
23. ——I did _____ here on time, but the traffic is terrible at this time, you know.
——Why don’t you ________ a bicycle to work?
A. try to get, try to ride B. try getting; try to ride
C. try to get; try riding D. try getting; try riding
