当状语从句的主语和主句的主语一致时,从句可以将主语和be动词简化掉。常用于以下几种情形:

1. 连词+形容词

As (he was) young, he learned how to ride a bike.他小时候就学会了骑自行车。

Whenever (she is) free, she often goes shopping.她有空就去逛商店。

Work hard when (you are) young, or you'll regret.少壮不努力,老大徒伤悲。

2. 连词+现在分词

As (she was) walking along the river bank, she was singing a pop song.她沿着河堤边走边唱着流行歌曲。

Although (he is) doing his best in maths these days, he has still got no good marks.尽管近来他一直在学数学,但他仍然没有取得好成绩。

3. 连词+名词

While (he was) a young boy, he was always ready to help others.他在孩子时代就乐于助人。

Although (he was) a farmer, now he is a famous director.尽管他曾是个农民,但现在他是位著名的导演了。

4. 连词+介词短语

She looked anxious as though (she was) in trouble.她看上去很焦急,好像遇到了麻烦。

He had mastered the English language before (he was) in the USA.他到美国之前就懂英语了。

注意:当从句主语和主句主语不一致时,从句部分要么用完全形式,要么用独立主格结构来表达。例如:

When the meeting was over, all the people went out of the meeting-room.当会议结束时,人们都走出了会议室。(=The meeting over, all the people went out of the meeting-room.)

5. 连词+过去分词

He won't go there with us unless (he is) invited.除非受到邀请,否则他不会和我们一道去那里。

The concert was a great success than (it was) expected.这场音乐会出乎意料地取得了巨大成功。

6. 连词+不定式

He stood up as if (he were) to say something.当时他站起来好像要说什么。

He wouldn't solve the problem even if (he were) to take charge.即使他来负责,他也解决不了这个问题。