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. —Would you mind if I sat here?
— Sorry. _____ I'm expecting a friend.
A. Of course not. B. I'd rather you didn't C. Go ahead. D. Why not?
22. _____ computer has been proved to be _____ important aid in classroom teaching.
A. The; an B. The; the C. A; the D. A; /
