文档介绍：主语从句
名词性从句包括:主语从句、表语从句、宾语从句和同位语从句。引导名词性从句的连词有:
:that, whether, if(这三个词都不作从句的成分,同时,that无含义,而whether和if都表“是否”)
:who, whom, whose, what, which
:when, where, why, how
(一)主语从句:在复合句中充当主语的从句。
that引导主语从句时不同于其他的连词,既无词义也不作成分,只起单纯的连接作用,且通常不可以省。为了强调that引导的主语从句而置之于句首时,that不可省。
①That the driver could not control his car was obvious. 很明显司机不能控制住他的车了
②That she was chosen made us very happy. 她被选上让我们很高兴
③That he e is certain. 他要来已经千真万确了
★通常,that引导主语从句时用it做形式主语,把从句置于句尾,此时that有时可省。例如:
①It was obvious that the driver could not control his car. 很明显司机不能控制住他
②It made us very happy that she was chosen. 她被选上让我们很高兴
③It is certain that he e. 他要来已经千真万确了
★如果以that从句为主语的句子是疑问句,就只能用先行词it结构。例如:
①Is it certain that he e?
②Is it true that he would take the risk?
▲it做形式主语有以下几种不同的结构:
(1)It + be + 形容词+ that-从句
①It is likely that he e. 他可能会来
②It is strange that she has ever trusted him. 她相信他,真令人奇怪
(2)It + be +名词+ that-从句
It mon knowledge that the whale is not a fish. 鲸鱼并不是鱼,这是常识
It's a pity that he should have catched the train.
(3) It + be + -ed分词+ that从句
It is said that he is a famous writer. 据说他是个著名作家
It is reported that there will be a storm this afternoon. 据报道下午将有一场暴风
▲在表示建议、要求、命令等意义的被动结构中,that从句中的谓语动词常用(should) do。(参见虚拟语气部分)
It is suggested that the meeting (should) be held this afternoon. 会议被建议在下午举行
It is demanded that he (should) leave at once. 他被要