27. The weather is concerned with all of us because it ____ us so directly -- what we wear, what we do, and even how we feel.

　 A. effects　　 B. guides　　 C. affects　　 D. benefits

26. I ___ in a government office for five years. Still, I don’t regret giving up the admirable job.

　A. have worked B. worked C. was working D. had worked　

25. Many Chinese airline companies had intended to get much of the business, but it ___ so bad.

　A. made out B. turned out C. went out D. carried out

24. Is this radio the one you would like ____?

A. to have it repaired B. to have repaired C. to repair it D. have it repaired

23. With so many programs ____ online for free, there is no excuse no to make use of them.

　A. available B. acceptable C. approachable D. movable

22. -How did you feel when you saw the 2009 National Day military parade in Tiananmen Square?

-Wonderful. I couldn’t be ____.

A. very exciting　　 B. more excited　　　　 C. most excited　　　　 D. less excited

第一节 单项填空(共15小题，每小题1分，共15分)

从每题所给的A. B. C.D四个选项中，选出可以填入空白处的最佳选项，并在答题卷上做答。

21. Zhang Xuan, ____ university student from Shanghai, learns ____ art in her spare time. A. an; /　B. a; the　C. a; /　D. an; the

1． 假设每一架飞机引擎飞机中故障率为P，且个引擎是否发生故障是独立的，如果有至少50%的引擎能正常运行，问对于多大的P而言，4引擎飞机比2引擎飞机更安全？

解　 飞机成功飞行的概率：

^{4引擎飞机为：}

2引擎飞机为：

要使4引擎飞机比2引擎飞机更安全，只要

所以