一、 单项选择（15小题，每小题1分，共15分）
从A、B、C、D四个选项中选出一个最佳答案，将其标号填入题前括号内。
( D ) 21. The number of students who _____________ the English club ______20.
A. take part in, is B. join, are C. take part in, are D. join, is
( A ) 22. ---- Could you please tell Jim that I will call him later?
---- Sure. I’ll tell him when he __________.
A. comes B. came C. has come D. will come
( C ) 23. They waited and waited for something _________ to happen.
A. excite B. excited C. exciting D. to excite
