高中英语学习方法：最常考的八类状语从句（2）

四、when引导的状语从句

对于when的用法，同学们最熟悉的是表示“当……的时候”。如：

—Where’s that report?

—I brought it to you ______ you were in Mr. Black’s office yesterday. (北京卷)

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

【解析】答案选B。将四个选项逐一填入空格处，只有填when时，意思最通顺。句意为：当你昨天在布莱克先生办公室时我就带给你了。

但是when还有一个用法，就是表示“既然”。如：

Why do you want a new job ___D___ you’ve got such a good one already?

A. that B. where C. which D. when

还有一点也需注意，就是when表示“这时(突然)”的用法。如：

1. I had just stepped out of the bathroom and was busily drying myself with a towel ___B___ I heard the steps. (湖南卷)

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

2. He was about halfway through his meal ___C___ a familiar voice came to his ears. (辽宁卷)

A. why B. where C. when D. while

五、unless引导的状语从句

unless的意思是“如果不……”“除非”，对于涉及unless的考题，一般只要能读懂句意，弄清语境，一般不会有问题。如：

1. Most birds find it safe to sleep in the trees, but ______ they have eggs or young chicks, they don’t use a nest. (湖南卷)

A. why B. how C. unless D. where

2. I won’t call you, ______ something unexpected happens. (全国I)

A. unless B. whether C. because D. while

【解析】两道题都选unless，均表示“除非”。