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。
21.Of all the subjects, I like geography best mainly because it gives us
useful knowledge of the world we live in.
A. the; a B. /; a C. a; the D. the; an
22.I passed by the sports field yesterday, ___there was a football match going on then.
A. that B. where C. which D. when
