II. 单项选择（每小题0.5分，共10分）
从A、B、C、D中选出能填入空格的最佳答案。
21. In those days, the old woman________ sit at the door for hours, waiting for her son to return from abroad.
A. could B. should C. might D. would
22. I’d like to buy a house ---modern, comfortable, and _________ in a quiet neighborhood.
A. in all B. above all C. after all D. at all
23. Mark was a student at this school from 2009 to 2012, ______ he studied very hard and was made Chairman of the Students' Union.
A. by that time B. for which time C. during whose time D. during which time
24. ---I need some fresh air, so I’m going out for a walk.
---________.
A. Have fun B. With pleasure
