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 professor has ______ 11-year-old boy who has______ gift for dancing.
A. a; a B. an; the C. an; a D. the; 不填
22. After the traffic accident, no one______ except a few people who were badly injured.
A. survive B. was survived C. survived D. was surviving
23. ______ is known to everybody that the moon travels around the earth once every month.
A. It B. As C. That D. What
