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。
21. I’ve found that many people are still in habit of writing silly things in public places.
A. the ; the B. /;/ C. the ; / D. / ; the
22. Jerry more time playing football than learning.
A. costs B. takes C. spends D. pays
