英语主语从句的短文

主语从句
1、定义：先找到句子的谓语,主句的谓语前面的从句,叫做主语从句.
Why he left wasn't important.(wasn't是主句的谓语动词,why he left做主语从句)
That she became an artist may have been due to her father's influence.(may have been due是主句的谓语动词,that she became an artist做主语从句)
2、借助形式主语it,主语从句放在后面
①由that引导的主语从句可以放在主语的位置,这时that不可以省略.例如：That prices will go up is certain.
that主语从句放在句首的情况不是很常见,绝大部分主语从句都借助形式主语it,主语从句放在后面.
It is strange that he knows nothing about it.
It is a pity that he can't swim.
It happened that he wasn't in that day.
It is said that there has been an earthquake in India.
在口语中,用it做形式主语时,主语从句的that可以省略.
②wh-疑问词引导的主语从句,可以放在句首(第一组),也可以借助形式主语it(第二组).
第一组：When he'll be back depends much on the weather.
How it was done was a mystery.
Whether we'll succeed remains to be seen.
第二组：It is uncertain whether the game will be held.
It's a puzzle how life began.
It doesn't matter much where we live.
Is it known where he went?