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. He will _____ our class to sing at the school singing contest.
A. take place of B. stand for C. represent D. representative of
22. The two boys fought and fought until one ______.
A. gave up B. gave in C. gave D. gave off
