第二部分：知识运用（共两节，45分）
第一节 单项填空（共15小题：每小题1分，共15分）
从每题所给的A、B、C、D四个选项中，选出可以填人空白处的最佳选项，并在答题卡上将该项涂黑。
21. ______your compositions carefully and some spelling mistakes can be avoided.
A. Having checked B. Check C. Checked D. Tocheck
22. John returned with two workers, with_______ help we finally got the car out of the mud.
A. whose B. their C. which D. that
23. ---Who’s the man talking to our teacher?
---A professor_____a visit our school.
A. pays B. to pay C. paid D. paying
