第二部分 英语知识应用（共两节，满分45分）
第一节 单项选择（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 took _________of the fine weather today to play tennis.
A. care B. charge C. note D. advantage
22. The old woman has two sons, one is a teacher.
A. of who B. of whom C. of which D. of them
23. Our manager is _______ an important customer now and he will be back this afternoon.
A. calling on B. calling in C. calling up D. calling for
