第一节：单项填空（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．---Steve, we will take an exam in physics next week.
---Yes, but don’t work too hard. ________.
A. It doesn’t matter B. All the best
C. Take it easy D. Try your luck
22．Now the situation is getting worse. We can’t ignore the bad ______ air pollution is having on the environment.
A．result B．impression C．reputation D． effect
23．Remember to take a breath of ______ fresh air and have some exercise each day. It will make ______
