31. I often visited Tian’an Men Square ____________I was staying in Beijing.

A. until　　　　 B. during　　　　　 C. while　　　　　　　 D. throughout

30. I don’t think you’ll be able to understand this formula(公式) ____________you finish school.

A. as if　　　　　 B. only when　　　　　　　　 C. even　　　　　 D. even when

21-25 BAABA　 26-30 CDDDD

29. __________I saw the computer, I showed great interest in it.

A. At first　　　 B. For the first time　　　　 C. Until　　　　　　 D. The first time

28. Try _______he might, he couldn’t get out of difficulty.

A. when　　　　　 B. where　　　　 C. till　　　　　　　　 D. as

27. He speaks English _____________he speaks his mother tongue.

A. so good as　　　　 B. as good as　　　　　 C. so well as　　　　　 D. as well as

26. It is ten years ____________I left home.

A. when　　　　 B. after　　　　　　 C. since　　　　　　　 D. as

25. Why not buy a cheaper one, _____________you don’t have enough money?

A. since　　　　　 B. because　　　　 C. for　　　　　　 D. though

24. It was __________it rained heavily that they didn’t come.

A. as　　　　　 B. because　　　　　 C. for　　　　　　　 D. since

23. -Why do you drink so much coffee?

-Well, _________it doesn’t keep me awake in the nights, I see no harm in it.

A. although　　　 B. if　　　　 C. unless　　　　　 D. while

22. Not until all the fish died in the river __________how serious the pollution was.

A. did the villagers realize　　　　　　　 B. the villagers realized

C. the villagers did realize　　　　　　　 D. didn’t the villagers realize