爱华网
定语从句
状语从句
名词性从句
一、主语从句
在复合句中充当主语，通常放在主句谓语动词之前或由形式主语it代替，而本身放在句子末尾
引导词：that, whether(if), who, what, which, whoever, whatever,whichever, whatsoever
用 法：
1. it作形式主语和it引导强调句的比较
it作形式主语代替主语从句，主要是为了平衡句子结构，主语从句的连接词没有变化。
it引导的强调句是对句子某一部分进行强调，常用that作为连接词，强调人时也可用who/whom。
It is a pity that you didn't go to see the film.
It doesn't interest me whether you succeed or not.
It is in the morning that the murder took place.
It is John that broke the window.
2. 用it作形式主语的结构
1) It is + 名词 + 从句
It is a fact that ...
It is an honor that ...
It is common knowledge that ...
2) It is + 形容词 + 从句
It is natural that ...
It is strang that ...
3) It is + 不及物动词 + 从句
It seems that ...
It happened that ...
4) It + 过去分词 + 从句
It is reported that ... 据报道...
It has been proved that ... 已证实...
3. 主语从句不可位于句首的五种情况
1) if 引导的主语从句不可居于复合句句首。
2) It is said , (reported) …结构中的主语从句不可提前。例如：
It is said that President Jingo will visit our school nextweek. (right)
That President Jiang will visit our school next week issaid. (wrong)
3) It happens…, It occurs… 结构中的主语从句不可提前。例如：
It occurred to him that he failed in the examination.(right)
That he failed in the examination occurred to him.(wrong)
4) It doesn’t matter how/whether …结构中的主语从句不可提前。例如：
It doesn’t matter whether he is wrong or not. (right)
Whether he is wrong or not doesn’t matter. (wrong)
5) 含主语从句的复合句是疑问句时，主语从句不可提前。例如：
Is it likely that it will rain in the evening? (right)
Is that will rain in the evening likely? (wrong)
4. What 与that 在引导主语从句时的区别
What 引导主语从句时在从句中充当句子成分，如主语．宾语．表语，而that 则不然。例如：
1) What you said yesterday is right.
2) That she is still alive is a consolation.
注意：
主语从句的时态不受主句时态的影响和限制,多数情况下视为第三人称单数，但也有例外
二、表语从句 Top
在复合句中作表语的名词性从句，放在系动词之后，一般结构是“主语＋连系动词＋表语从句”。
连接词：
可以接表语从句的连系动词有be, look, remain, seem等。引导表语从句的that常可省略。另外，常用的还有thereason is that… 和It is because 等结构。
1) The question is whether we can make good preparation insuch a short time.
2) This is why we can’t get the support of the people.
3) But the fact remains that we are behind the otherclasses.
4) The reason he is late for school is that he missed theearly bus.
三、宾语从句 Top
四、同位语从句 Top
