［答案］ D. 

［析］ or这里应译为：否则。

3 I'll give the book to him ＿＿＿ he comes back.

A. since B. as soon as

C. before D. until 

［答案］ B. 

［析］ as soon as 引出的时间状语从句应用一般现在时表示将来要发生的动作。

4 Don't cross the road ＿＿＿ the light turns green.

A. when B. while

C. until D. as 

［答案］ C. 

［析］ until应译为"直到……才"，因为前面的祈使句为否定句。又如：She did not go to bed until her mother came back. 应译为"直到她妈妈回来她才睡觉"。

5 Miss Gao has been a teacher ＿＿＿ 1990.

A. before B. after

C. since D. in 

［答案］ C. 

［析］ 因为主句为完成时，所以应用 since表示该动作的启始点。

6 - Which would you like better, tea ＿＿＿ milk?