1. that 引导主语从句时,that 没有意义,但不能省略。(that 引导宾语从句时可以省略。)
For example:
It worried her a bit that her hair was turning gray. 她的头发正在变白,这使她很不安。that引导主语从句,it 作形式主语,that 不能省略。
That she is a rich woman is known to us all. 众所周知,她是个富有的女人。这是that 引导主语从句,that 不能省略。这句话可以改为用it 作形式主语的句型。请同学们改写:It is known to us all that she is a rich woman.)
We didn’t know (that) you had sold your house. 我们不知道你已经把你的房子卖了。这是that引导宾语从句,that 可以省略。注意这句话的时态。
2. 从句作主语时,多数情况下由 it 作形式主语,而把主语从句放在后面,尤其是谓语部分(包括宾语)较短的情况下。
For example:
It wasn’t very clear what she meant. 不清楚她是什么意思。
It is important that he should come on time. 他按时来是很重要的。
It is true that that man on the left is a well-known writer here. 左边那个人是本地的一位著名作家,这是真的。这里,第一个that 引导主语从句,是单纯的连词,无词义,不作句子成分。第二个that 是指示代词,作句子成分,是man 的定语。