主语从句

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所属类别 : 语法

主语从句，即在复合句中充当主语成分的句子，例如"That he finished writing the composition in such a short time surprised us all"，他在很短的时间内写完作文让我们都很惊讶，此复合句主要描述的是某事让我们惊讶，某事就是该复合句的主语，因此"That he finished writing the composition in such a short time"便是该复合句的主语从句。

引导主语从句的连词主要有:

从属代词:that whether

连接代词:who whoever whom whose what whatever which whichever

连接副词:when where how why

基本信息

• 中文名称

  主语从句 

 

• 外文名称

  Subject clause

目录	1定义	2第一部分	3第二部分

折叠编辑本段定义

在复合句中充当主语成分的句子叫做主语从句。

一.

引导主语从句连词有that,

who,what,whatever等 定义:如果一个句子在复合句中充当一个主语,那么这个句子就是主语从句. 第一部分：常规主语从句，即句子在复合句中充当一个主语 

（1）That he finished writing the composition in such a short time surprised us all. 

（2）Whether we will go for an outing tomorrow remains unknown.

（3）Who will be our monitor has't been decided yet. 

（4） Whom we must study for is a question of great importance. 

（5）What caused the accident remains unknown. 

（6）Whatever you did is right. 

（7）Whose watch was lost is unknown. 

（8）What we need is time. 

（9）What we need are good doctors. 

小结: （1)引导主语从句连词有that,whether,who,what,whatever等 （2)连词位于句首不能省略 （3)主语从句大多数情况下视为单三,但也有例外,如例9 第二部分：为了防止句子头重脚轻，通常把形式主语it放在主语位置，真正主语搁置于句末 

（1）It is certain that he will win the match. 

（2）It is true that he has made a very important discovery in chemistry. 

（3）It is very likely that they will hold a meeting. 

（4）It is strange that he should do that. 

（5）It is important that we all should attend the meeting. 

（6）It is strange that the man should have stuck to his silly ideas. 

（7）It is a pity that we won't be able to go to the south to spend our summer vacation. 

（8）It is still a mystery what caused the accident. （9）It is said that he has gone to shanghai.(=He is said to have gone to shanghai)

（10）It is known to all that the gun powder was first invented by the Chinese. 

（11）It is suggested that the work should be done with great care. 

（12）It seems that he has seen the film.(=He seems to have seen the film) 

（13）It happened that the two cheats were there. (=The two cheats happened to be there) 

小结: （1)以that 引出的主语从句,常以形式主语it引导.  It is +形容词/名词/某些动词ed + that 从句. （2) 在有些that从句中要用虚拟语气  (should+do/should+have done)  

二、主语从句与形式主语it

有时为了考虑句子平衡，通常在主语从句处使用形式主语it，而将真正的主语从句移至句末。这分三种情况：

(1) 对于以连词that引导的主语从句，通常用形式主语代主语从句：

It’s a pity that he didn’t come. 很遗憾他没来。

It is important that he should know about this. 他必须知道此事。

It’s vital that we bepresent. 我们出席是至关重要的。

Itwasintendedthatyoubethecandidate. 大家的意图是让你当候选人。

Itisimportantthatthismissionnotfail. 这项使命不失败至关重要。

Itisessentialthatameetingbeconvenedthisweek. 本周开一次会非常重要。

Itisappropriatethatthistaxbeabolished. 废除这个税是恰当的。

It’sunfairthatsomanypeopleshouldlosetheirjobs. 竟有这么多人失业这是不公平的。

It’samazingthatsheshouldhavesaidnothingaboutit. 她竟未谈及此事令人惊讶。

It’sunthinkablethattheyshoulddenymyrequest. 他们竟然拒绝我的请求，这是不可思议的。

Thattheyshouldrefusetosignthepetitionrequiredgreatcourage. 他们拒绝在请愿书上签字这是需要很大勇气的。

(2) 对于以连接代词(副词)引导的主语从句，可以使用形式主语代主语从句，也可直接在句首使用主语从句：

Whethertheywouldsupportuswasaproblem. 他们是否会支持我们还是一个问题。

Itwasaproblemwhethertheywouldsupportus. 他们是否会支持我们还是一个问题。

Itremainstobeseenwhetheritwilldousharmorgood. 它对我们是利是害，还得看看再说。

(3) 对关系代词型what引导的主语从句，通常直接将主语从句放在句首。如：

Whatweneedismoney. 我们需要的是钱。

WhatIwanttoknowisthis. 我想知道的就是这一点。

有时也可将助用形式主语。如：

Itisclearenoughwhathemeant. 他是什么意思很清楚。

(4) 如果句子是疑问句，则必须用带形式主语it的结构：

Isittruethatheisthegirl’sfather? 他是那女孩的父亲，是真的吗？

Howisitthatyouarelateagain? 你怎么又迟到了？

that

引导主语从句的连词that 有时可省，有时不能省，其原则是：若that引导的主语从句直接位于句首，则that不能省略；若that引导的主语从句位于句末，而在句首使用了形式主语it，则that可以省略：

Thatyoudidn’tgotothetalkwasapity. 很遗憾你没去听报告。(that不可省)

Itwasapity (that) youdidn’tgotothetalk. 很遗憾你没去听报告。(that可省)

折叠编辑本段第一部分

常规主语从句，即句子在复合句中充当一个主语

主语从句的时态：不受主句的时态影响和限制。

（1）That he finished writing the composition in such a short time surprised us all.

（2）Whether we will go for an outing tomorrow remains unknown.

（3）Who will be our monitor hasn't been decided yet.

（4）Whom we must study for is a question of great importance.

（5）What caused the accident remains unknown.

（6）Whatever you did is right.

（7）Who the watch belongs to is unknown.

（8）What we need is time.

（9）What we need are good doctors.

小结

（1）引导主语从句连词有that,whether,who,what,whatever等

（2）连词位于句首不能省略

（3）主语从句大多数情况下视为第三人称单数，但也有例外，如例（9）

折叠编辑本段第二部分

为了防止句子头重脚轻，通常把形式主语it放在句首位置，真正主语搁置于句末

（1）It is certain that he will win the match.

（2）It is true that he has made a very important discovery in chemistry.

（3）It is very likely that they will hold a meeting.

（4）It is strange that he should do that.

（5）It is important that we all should attend the meeting.

（6）It is strange that the man should have stuck to his silly ideas.

（7）It is a pity that we won't be able to go to the south to spend our summer vacation.

（8）It is still a mystery what caused the accident.

（9）It is said that he has gone to shanghai.(=He is said to have gone to shanghai)

（10）It is known to all that the gun powder was first invented by the Chinese.

（11）It is suggested that the work should be done with great care.

（12）It happened that the two cheats were there. (=The two cheats happened to be there)

小结:

（1）为避免头重脚轻，常以形式主语it引导从句。 It+形式主语谓语+从句。

（2）由于主语从句一般被认为是单数形式，形式主语的谓语动词、be动词+表语 均为单数第三人称形式或过去式.

注意：当what引导的名词性分句作主语时，主谓一致问题极为复杂。著名学者周海中教授在论文《关于what-分句作主语的主谓一致问题》中就这一问题做了深入研究，并给出了10种的主谓一致关系。这些一致关系值得英语学习者和使用者特别注意。

主语从句的用法

主语从句与宾语从句两者的用法和在句中的作用是不同的，下面从它们的各自用法来介绍。

一．主语从句

主语从句 定义：在句子中担当主语的是一个从句，这个从句就叫做主语从句。

主语从句是在复合句中充当主语的从句，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。

1. It 作形式主语和it引导强调句的比较

①主语从句常用it作形式主语，一般常用句型为：It is+{名词/形容词/过去分词}+主语从句例如：

It is still a question whether she will come or not.

It is strange that you should like him.

It is still unknown which team will win the match.

另外，还有一些比较多见的结构：

It turned out that……;

It has been proved that……;

It happened/occurred that……;

It is well-known that……等等

②而强调句则不同，它的结构是：It+be+被强调部分+that+从句

强调主语：It is the times that produce their heroes.时势造英雄

强调宾语：It is English that Prof.Lin teaches us.

强调状语：It was in shanghai that I saw the film.

判断是否是强调句有一个方法，就是将that以后的“句子的其余部分”拿出来单独看，看有没有缺成分，缺的是什么成分，再把谓语动词后面that前面的那部分，带到你认为缺成分的地方，如果放进去是一句完整的句子了，那就说明是强调句。

2. 用it 作形式主语的结构

(1) It is +名词+that从句

It is a fact that … 事实是……

It is an honor that …非常荣幸

It is common knowledge that …是常识

(2) it is +形容词+that从句

It is natural that… 很自然……

It is strange that… 奇怪的是……

(3) it +不及物动词+that从句

It seems that… 似乎……

It happened that… 碰巧……

(4) it is+过去分词+that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 next week.

(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.

(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.

(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?

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：

What you said yesterday is right.

二：宾语从句用以区分主语从句的几个特征：

1、引导词：what\which\whose\when\whether\if\where

2语序：宾语从句必须是用陈述语句。

如：I think that you must work harder.

宾语从句的引导词、连接词的区别、否定转移等现象。

(1)表达时间的几个句型：一般用when或者是what time：

What time will the train leave?

由于时刻都是固定的，也可以用一般现在时代替一般将来时：

What time does the train leave?

(2)时间的表达方式：8：19(nineteen past eight),7:57(three to eight)，在时间的中间也可以加上分的单词(minutes)

(3)had better +动词原型。意思是提要求，建议。但是上下级不能用这种方式，因为语气太重：

You had better give up smoking .

(4)sb leave sth +地点

I left my book in my classroom yesterday.

(5)may I have your name(address\age)?一般询问对方的年龄、名字等，不要习惯以前的问法，这样很不礼貌，而是要采访上面的问法。以前的习惯是：how old are you? \what's your name?

(6)修饰名词的代词次序：限-描-大-形---年---颜----籍----物--------类+名词：

this is a bridge.

This is a beautiful bridge

补充：从句的语序永远是陈述句。[1]