3.[解析] 选B。题意为：他们注视着这个人一直到他消失了。此题考查重点词汇在不同语境中的应用差异。see意为“看见” ，watch意为“注视”，notice 意为“注意到”，look 意为“看(着)”。根据句意和它们之间的用法差别，应选B。

2.[解析] 选A。题意为：当心！有一辆车来了。此题考查重点短语的应用。B项意为“环顾四周”，C项意为“朝前看”，D项意为“看待”。根据句意，A项最合适。故选A。

1.[解析] 选A。题意为：尽管很多困难，他们不打算放弃这个计划。此题考查重点词汇在语境中的应用。B give in 意为屈服，C arrange 安排，D lose 失去，A abandon 放弃，故选A。

15. We all know that he always tries his best ____ the people in trouble.

A. to helping　 B. in helping　 C. to help　 D.helps

答案解析：

单项填空：

14. We are all wondering why Tom ______us　 recently.

　A. hasn’t written　 B. doesn’t write　 C.won’t write　 D. hadn’t written

13. 13. The founding of the new country is a great ___ in the history.

A. accident　 B. business C. matter　 D. event

12. ---Jerry is not coming .

　 ---But she ____.

A. promises 　B. promised C. will promise D. had promised

11. The food tastes terrible. It seems ____ bad.

A. to have gone 　B. having gone 　C. to go 　D. that it went

10. I got ____ when I heard that he failed the exam.

A. confuse B. confused 　C. confusing 　D. to confuse

9. If you keep on ,you will succeed ___.

A. at the same time 　B. on time 　C. for time　 D. in time