第二部分 英语知识运用（共两节，满分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. As far as we know, half of Canadian teenagers do not get enough sleep on school nights, _____?
A. do they B. don’t they
C. don’t you D. isn’t it
22Take care! There is a nail______of the chair.
A. sticking out B. putting out C. standing out D. giving out
23A terrible earthquake struck Wenchuan, Sichuan Province on May 12th,_____more than 60,000 deaths.
A. caused B. having caused C. to have caused D. causing
24But the unpleasant feeling of coldness disappeared at the _______ of his students pouring out of their classroom to give him a warm, wordless welcome.
A. sight B. scene C. view D. sign
25They no longer have to ______ large numbers of temporary workers to do the harvesting.
