19. -________I’m going to the post office.

-________ you’re there, can you get me some stamps?

A. As　　 B. While　　 C. Because　 D. If

答：B。while可指时间的一段，而when常指时间的一点。as常表示两个司作同时进行。while当……时。

18. Would you like a cup of coffee________ shall we get down to business right away?

A. and　　 B. then　 C. or　　 D. otherwise

答：C。or或者otherwlse否则，要不然的话，与句意不符。

17. If we work with a strong will, we can overcome any difficulty, _______great it is.

A. what　 　　　B. how

C. however 　　D. whatever

答：C。however接形容词或副词引导让步状语从句，whatever接名词。如：We will succeed whatever difficulties we meet。

16. -Isn’t he a student?

-________. It is two years since he was a college student.

A. Yes, he is　　　　　 B. No, he isn’t

C. Yes, he isn’t　　　　　 D. No, he is

答：B。“it is+时间+since”句型若接延续动词则译为“他不……多久了”。此题译为“他大学毕业两年了。”

15. It won’t be long _______ we meet again.

A. since　　 B. before　 C. if　　　 D. when

答：B。“it won’t be十时间+before”意为“不久……就……”

14. He had left _______ I could thank him.

A. before　 B. after　　 C. if　　　 D. unless

答：A。before表示动作的快，意为“还没……就……”。

13. I was just about to go out ________ the phone rang.

A. while　　 B. as　　 C. when　　 D. since

答：C。when相当于atthat time就在那时。此用法不能用其他词代替。

12. _______we are close friends, we also have different opinions.

A. When　　 B. While　 C. Unless　 D. Once

答：B。while=although 虽然

11. She thought I was talking about her daughter, ________, in fact, l was talking a-bout my daughter.

A. who　　 B. where　 C. which　　 D. while

答：D．while表示“而……”，含有对比之意。

10. Mother was worried because little Alice was iii, especially _______ father was a-way in France.

A. as　　　 B. that　　　 C. during　　 D. if

答：A．as为连词相当于when，而during为介词，一般不接从句。