第二部分：（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，并在答题卡上将该项涂黑。
21. Every evening after dinner, if not _______ from work, I will spend some time
walking my dog.
A. being tired B. tiring C. tired D. to be tired
22. Most Americans would prefer to keep their problems themselves, and
solve their problems ______ themselves.
A. to; by B. by; to C. for; to D. in; on
