第二部分:英语知识运用(共两节,满分 45分)
第一节    单项选择(共15小题;每题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. Such ____ medical equipment is in ____ danger of breaking down, if not taken good care    
   of.
A. a; the                B. a; /                   C. /; the                 D. /; /
22. ____ the working efficiency(工作效率), the boss allows the employees to have a coffee   
   break.
       A. Improving                                     B. To improve
       C. Having improved                           D. Improved