第二部分：英语知识运用（共两节，满分45分）
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.The bird ______ its wings and flew to the south.
A. beat B. hit C. strike D. struck
22. Dr. Frank failed many times but he finally to find a successful way to solve the problem.
A. broke off B. broke up C. broke down D. broke through
