第二部分：英语知识运用（共两节，满分40分）
第一节 单项填空（共20小题；每小题1分，满分20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. — Waiter!
— ______
— I can’t eat this. It’s too salty.
A. What? B. Yes, sir? C. All right? D. Pardon?
22. Hiking is ______ great fun. You will get close to ______ nature and take exercise at the same time.
A. a; the B. a; 不填 C. 不填; the D. 不填; 不填
23. — Why does the lake smell terrible?
— Because large quantities of water ______.
A. have polluted B. is being polluted C. has been polluted D. have been polluted
24. At the beginning of class, the noise of desks ______ could be heard outside the classroom.
