主语从句讲解

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主语从句讲解及习题

名词性从句之主语从句一、名词性从句概述：在句子中起名词作用的各种从句统称为名词性从句。

根据它们在句中的语法作用，这类从句又可分为主语从句、同位语从句、表语从句和宾语从句。

二、主语从句定义：在句中起主语作用的从句称为主语从句。

引导主语从句的连接词主要有：单纯连词(that, whether/ if)、连接代词(what, whatever, who, whoever, whom, whose, which, whichever 等)和连接副词(when, where, why, how, whenever, wherever, however 等)。

1)that引导的主语从句(1)由连词that引导的主语从句:引导词that无含义/在句中不做成分/不可以省。

例如：That you will win the medal seems unlikely.你能得奖看起来不大可能。

That light travels in straight lines is known to all.众所周知，光沿直线传播。

That you don’t like him is none of my business.你不喜欢他不管我的事。

(2)形式主语it替代主语从句位于句首，that引导真正的主语从句会放到句子的后面。

常用的句式主要有如下几种：1.It+系动词+形容词+that从句。

如：It is necessary that … 有必要 .....It is clear that … 很清楚.....It is likely that … 很可能.....It is important that … 重要的是.....类似的形容词还有：strange; natural; obvious; true; good; wonderful; possible; unlikely; quite; unusual; certain; evident; worth-while; surprising; interesting; astonishing, etc.例如：It was really astonishing that he refused to talk to you.It is essential that he should be here by the weekend.It seems obvious that we can not go on like this.It is necessary that you (should)master the computer.It is important that a student learn English well.It' s clear that they badly need help.It is likely that a hurricane will arrive soon.知识拓展：在“It is necessary / important/surprising/strange/unthinkable/unbelievable/incredible+that 从句”这类主语从句结构中，从句中谓语动词常用(should) +动词原形”，形式，即要用虚拟语气should 可省略。

主语从句讲解及练习

主语从句讲解及练习什么是主语从句？主语从句是由一个从句充当主语的句子结构，它由连接词引导，用来说明主语的内容或者起到引入主题的作用。

主语从句的引导词一般情况下，主语从句由以下连接词引导：- that- whether/if- who/whom- which- what- whatever- whoever- whichever主语从句的用法主语从句在句子中承担主语的角色，可以帮助我们表达某个动作、状态、事件或者事实的主题。

下面是一些常见的用法示例：1. 表达事实或真理：例如：That he is innocent is beyond doubt.（他的无辜是毫无疑问的。

）2. 表达感觉或观点：例如：What he said is very interesting.（他说的话很有趣。

）3. 引导宾语从句：例如：I believe that he will succeed.（我相信他会成功。

）主语从句的位置一般情况下，主语从句位于句首或者句中，具体位置取决于句子的结构和语境。

主语从句的练题请根据下面的句子，填写合适的主语从句：1. __________ you did yesterday surprised everyone.（你昨天做的事让大家都吃惊。

）2. __________ will happen remains unknown.（将会发生什么还不确定。

）3. __________ is important to study hard.（努力研究是很重要的。

）5. __________ we need is more time.（我们所需要的是更多的时间。

）参考答案：1. What2. What3. It4. Whether/if5. What以上是对主语从句的讲解及练习，希望对你的学习有所帮助。

主语从句超全讲解加练习

1〕从属连词：that，whether等.that 引导主语从句只起引导作用，本身无实际意义，在主语从句中不充当任何成分，但不能省略。

That he will win is certain.他肯定会赢。

Whether he’ll come here isn’t clear. 他是否会来这里还不清楚。

注意: 由that 引导的主语从句有时为了使句子结构平衡, 防止“头重脚轻”, 常用it 作形式主语, 而把从句放在后面。

例如:1. That he will refuse this piece of advice is impossible.2.That they should like each other is natural.这样就构成了下面一些常用句型:1) It is + n. +从句It is a pity/shame that... 遗憾的是……It is a surprise that…令人惊奇的是…It is a fact that… …是事实It is common knowledge that… …是常识______________(很遗憾)we lost the match._____________(这是事实)he cheated in the exam.2) It is + adj. +从句It’s certain that… 肯定…It is possible that... 很可能……It is unlikely that... 不可能……It is obvious that… 很明显…It is necessary \important \natural\... that…+(should) do________________(很可能)she will come back tomorrow.*_________________(很明显)this measure is effective.3) It +不及物动词+从句It happened that... 碰巧……It occurred to me that…我突然想起…_______________(刚好)I came into the office at that time.*____________________(我突然想起)I forget to sent the letter.4) It + be +过去分词+从句It is said that... 据说……It is known to all that... 众所周知……It is reported that... 据报道……It is believed that..人们相信/认为……It is suggested that + (should〕do... 建议……__________________(据报道)20 people were killed in the accident.*_______________(建议)we should eat more vegetable and do more exercise.2.连接代词who ，what ，which, whatever, whichever, whoever(Who, whom, which, what可以和ever构成合成词，和what一样引导从句，ever起到强调作用。

主语从句超全讲解加练习

2)wｈｅtｈｅr引导主语从句,ｉf不可
误:ＩfMaryrｅａllyｈｅaｒdhimis reallyｄoubｔｆul.
正: Wｈｅｔｈer Marｙrｅaｌlyheａrdhｉｍｉsｒｅａlly dｏubtful.
Cｏmpｌeｔetheｓｅntｅnｃｅs usｉng whａt, wheｔhｅr,ｗｈere,wheｎ, whｏ,ｗｈｙ, hｏwｏr tｈａt.
Wｈｅnｔhey wｉlllｅａvｅiｓｎoｔｄecided.
Howwewillpaint thehousｅhasnｏｔbeｅｎdecｉdeｄ.
注意:
1)主语从句在句首时，必须由连接词引导,不能省略这些连接词
误:Ｔｈey should lｉｋe eaｃh other isｎatｕrａl.
正：Ｔhａt thｅyshｏuld like each othｅrｉsnａtuｒal
(Who, whom，wｈicｈ，wｈat可以和ever构成合成词,和wｈat一样引导从句，ｅｖer起到强调作用。它们在句子中担任主干成分，并用陈述句形式)
What mａnｙｓcｉentiｓｔsｂｅlieve istｈaｔtｈe eartｈiｓrｏunｄ…
Whoｗｉｌl taｋｅpaｒｔin theｍeeting haｓｎoｔbｅen deｃidｅｄ.
Ｉt iｓobｖiｏus thａｔ…很明显…
Iｔｉs necｅssary＼ｉｍｐｏrtaｎｔ\natuｒaｌ\..．tｈat…+(sｈｏulｄ)do
_＿__＿_＿_＿__＿＿__＿（很可能）shｅwillcｏme bacｋtomorrow.
*＿__＿＿_＿__＿_____＿＿(很明显)ｔhiｓmeａsurｅiｓeffectiｖｅ.

(完整word版)主语从句讲解

主语从句1．定义：用作主语的从句叫做主语从句。

2．引导主语从句的关联词有三类：（1）从属连词that、whether。

如：如:That they were in truth sisters was clear from the facial resemblance between them。

很明显，她们确是亲姐妹，她们的脸型很相似.Whether he’ll come here isn’t clear。

他是否会来这里还不清楚。

从属连词：that， whether等.that 引导主语从句只起引导作用,本身无实际意义，在主语从句中不充当任何成分，但不能省略.由whether及其他连词引导的主语从句放在句首，句后都可. If只能放在句中.造句:1。

、很明显他是个好人.2。

、他通过了考试让妈妈很高兴。

3、天气是否会转晴还不确定。

(3）（特殊疑问词）连接代词who, whom， whose， what, which, whoever， whatever, whichever 如：__________watch was lost is unknown.__________she did is not yet known. 她干了什么尚不清楚.__________side will win is not clear。

__________comes is welcome。

不论谁来都欢迎。

__________ was said has left us much to think。

这里说的话都应当保密.造句：1. 我们需要的是时间。

2。

谁将成为我们的班长还没有决定。

3。

哪本书更好还不知道。

(4) （特殊疑问词）连接副词 where, when, how， why，wherever，whenever，however。

___________ he did it remains a mystery.When they will start is not known yet.How this happened is not clear to anyone。

初中语法主语从句讲解及(完整版)

主语从句：即在复杂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。

主语从句使用陈述语序，其通常结构为“引导词+ 主语+ 谓语+ 其他成分”；但当连接代词同时充当从句主语时，其结构为“连接代词+ 谓语+ 其他成分”。

时态：主语从句的时态不受主句时态的影响和限制引导主语从句的连词主要有:从属连词:that、whether （只起连接作用，不充当句子成分）连接代词:who、whoever、whom、whose、what 、whatever 、which 、whichever （既有连接作用，又做从句的主语、宾语、表语或定语）连接副词:when、where 、how 、why whenever、wherever（既有连接作用，又做从句的状语）例句：1. that引导例句：That you are coming to London is the best news I have heard this long time. 你将来伦敦是好久以来我听到的最好消息。

2. whether引导例句：Whether they would support us was a problem. 他们是否会支持我们还是一个问题。

3. 连接代词引导例句：Whoever is top from wins the game when two matched players meet. 两强相争勇者胜。

2023年高中英语语法精讲,主语从句详细讲解

2023年高中英语语法精讲—主语从句详细讲解主语从句结构及用法在句子中担当主语的从句就叫做主语从句，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。

通常结构为“引导词 + 主语 + 谓语 + 其他成分"。

一. 概念：在句子中担当主语的从句就叫做主语从句，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。

主语从句使用陈述语序，其通常结构为“引导词 + 主语 + 谓语 + 其他成分", 但当连接代词同时充当从句主语时，其结构为“连接代词 + 谓语 + 其他成分”。

二. 引导词：1. that引导eg. That you are coming to London is the best news I have heard this long time.2. whether引导eg. Whether they would come to conference was a question.3. 连接代词引导: who,whom, whose, what, which, whoever, whomever, whichever, whatevereg. Whoever is top from wins the game when two matched players meet.4. 连接副词引导: therefore, besides, otherwise, however, moreover, still, thus, meanwhileeg. How this happended is not clear to anyone.5. 关系代词型what引导三. 形式主语it:1. 对关系代词型what引导的主语从句，可以使用形式主语。

eg. It is clear enough what he meant.2. 如果句子是疑问句，则必须用带形式主语it的结构.eg. Is it true that all of us need to to conference?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。

主语从句讲解及其练习

主语从句一、主语从句的连词分三类（1）从属连词引导的主语从句（that whether if）that引导的主语从句:引导词that无含义/在句中不做成分/不可以省。

That 引导主语从句通常用it 作形式主语。

例如：That you will win the medal seems unlikely.That she survived the accident is a miracle.whether 引导的主语从句: whether有含义(是否)/在句中不做成分/不可以省。

注意：引导主语从句，不能用if不能在开头，只能用whether。

Whether we will hold a party in the open air tomorrow depends on the weather.Whether she is coming or not doesn’t matter too much.（2）用连接代词引导的主语从句在由连接代词who, whose, whom, which, what, whoever, whomever, whichever, whatever引导的名词性从句中，其连接代词在句中起名词性作用，担当一定成分.例如：What you need is more practice.Whatever we do is to serve the people.注：whatever / whoever的功用whatever, whoever在主语从句中不含疑问意义。

它引导主语从句，并在从句中作主语、宾语、表语等。

whatever = anything that; whoever = anyone who。

要注意和whatever, whoever引导的让步状语从句的区别。

如：Whoever breaks the law should be punished. （主语从句）（＝Anyone who breaks the law should be punished. ）Whoever breaks the law, he should be punished. （让步状语从句）（＝No matter who breaks the law, he should be punished. ）（3）用连接副词when, where, why, how引导的名词性从句(其连接副词有含义,在句中作状语。

主语从句讲解

主语从句讲解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任主语的从句，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.引导主语从句的关联词有三类：(1)从属连词that，whetherThat they were true sisters was clear from the facial resemblance between them.Whether he’ll come here isn’t clear.(2)连接代词who, whom, whose, what, which, whoever, whatever, whichever，What she did is not yet known.How this happened is not clear to anyone.Whoever comes is welcome.(3)连接副词where，when, how, why2.主语从句是在复合句中充任主语的从句，其功同名词一样。

为了避免头重脚轻，常用it作形式主语,而把真正主语放在句子末尾。

How the book will sell depends on its author.That he is the best student in the class is obvious.= It is obvious that he is the best student in the class.注意：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。

高考英语主语从句讲解

高考英语主语从句定义：用作主语的从句叫主语从句,它是名词性从句之一;主语从句的时态：不受主句的时态影响和限制;引导主语从句的连接词有：从属连词: that, whether；连接代词: who whoever, whom, whose, what whatever和which whichever；连接副词: when, where, how和why;连接词：1. 从属连词：that, whether1that引导主语从句只起引导作用,在主语从句中不充当任何成分,that本身无实际意义,但不能省略;2whether意为“是否”,放在句首句末皆可;由whether引导的名词从句做主语,表语,介词宾语,同位语时不可用if代替;price will go up is certain.b. Whether they would support us was a problem. 他们是否会支持我们还是一个问题;2. 连接代词who ,what ,which, whatever, whichever, whoever Who, whom, which, what可以和ever构成合成词,和what一样引导从句,ever起到强调作用;此类主语从句不能用形式主语it引导,它们在句子中担任成分,不能省略,语序为陈述语序,既有疑问含义,又起连接作用,同时在从句中充当各种成分;Which side will win is not clear. Whoever breaks the law will be punished. Whatever he did is right. Who killed the scientist remains a question.1What和that引导的主语从句的区别：that 只起引导作用,不充当任何成分,没有意思;What 不仅起引导作用,还要充当一定成分主语、宾语或表语,意思是：“什么”;What we need is money. That he will come is certain.2whatever / whoever的用法~ever=no matter ~---让步状语从句中whatever / whoever可以引导主语从句,并在句中作主语、宾语、表语等,不含疑问意义;whatever相当于anything that; whoever 相当于anyone who;例如: WhoeverAnyone who wants to enter into this school must take the exam.WhateverAnything that she did was right.3. 连接副词when,where, how,why等;既有疑问含义,又起连接作用,同时在从句中充当各种成分;Howthishappenedisnotcleartoanyone. When he will be back depends on the weather.When we’ll start tomorrow will be told soon. Where the test will be given is not yet decided.4. 主语从句后置：为了避免主语冗长,句子头重脚轻,经常用it 作形式主语,主语从句放在后面作真正的主语. 例: That we shall be late is certain. -- It’s certain that we shall be late.1用it 作形式主语的结构+ be + 形容词+ that 从句obvious,true,surprising,good,wonderful,funny,possible,likely,certain,probable,etc. 如：Itiscertainthatshewilldowellinherexam.+ be + 名词词组+ that 从句anhonour,afact,apity,etc如：It is a pity/shame that... 遗憾的是…… It is a surprise that…令人惊奇的是…It is a fact that… …是事实It is common knowledge that… …是常识It’sapitythatwecan’tgo.C. It + be + 过去分词+ that 从句said, reported, thought, expected, decided, announced, etc; 如：It is said that Mr. Green has arrived in Beijing.D. It + 不及物动词或短语+ that 从句seem,happen, doesn’t matter ,turnout ;如：It happened that I was out that day. It doesn’t matter whether she will come or not.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：a. Whether they would support us was a problem.b. It was a problem whether they would support us.3主语从句中的否定前移当用it作形式主语,而将主语从句放在句尾时,主语从句中的否定词常要前移至主句中;例如:It doesn’t see m that they are from the same university.It doesn’t appear that we’ll have a sunny day tomorrow.5. 注意：1主语从句在句首时,必须由连接词引导,不能省略这些连接词;误：They should like each other is natural. 正：That they should like each other is natural.2）在It + be + suggested/advised/ordered/requested/ insisted/required 中, that 从句的谓语也应该用“should + 动词原形”的形式, should有时可以省略;主语从句中用陈述语序,后面的谓语动词用第三人称单数. It is suggested that we should do the experiment a second time.3 . 用于It is important / natural / necessary / impossible that...句型中, 主语从句应使用虚拟语气, 用“should + 动词原形”的形式, should有时可以省略;It is important and necessary that we should keep the balance of nature.4“what”引导主语从句时,谓语动词：常与其后的名词作表语一致,且根据句子的语境而定;eg：What you left are only several old books. What you said is of great importance.5）在It is funny, strange, surprising, a pity, a shame, no wonder, etc. + that从句中,有时谓语部分用should + 动词原形,来表达说话者的感情色彩,此时should也可省略;6）语气"It be + adj./n. + that-clause"与强调句型均有It be...that...之类的语言标志,但不同的是:①前者中的that从句是主语从句.若删掉其中的It be和that,则剩余部分不论结构还是语意都不能成为一个句子;但若将后者中的It be和that去掉,则剩余部分的结构和语意仍能构成一个完整的句子.②强调句型译为汉语时可加上"正是……"或"就是……"之类的字眼,而主语从句则不可以.It is surprising that Mary should have won first place.令人惊奇的是玛莉竟然获得了第一名.It is Mary that has won first place.正是玛莉得了第一名.强调6..主语从句的规律：例will he come is not known. 正：When he will come is not known.规律一、主语从句一律用陈述语序,即主语在前,谓语在后;例2. He will not come to the meeting this evening is true.正：That he will not come to the meeting this evening is true.规律二、连词that 在从句中无实际意义,但不能省略;例3. If the meeting will be put off has not been decided yet.正：Whether the meeting will be put off has not been decided yet.规律三、whether 可以引导主语从句,放在句首,但if不能例4. That whether he will help others is a fact.正：That he will help others is a fact.规律四、主语从句中的连词不能重叠使用;例5. When he will come are a puzzle. 正：When he will come is a puzzle.规律五、含主语从句的主句谓语动词多用单数第三人称形式;1. What he needs is that book.2. What he needs are some books.规律六、what 引导的主语从句,可根据表语决定主句动词的单复数形式;规律七、主语从句为了避免头重脚轻现象,用it 做形式主语,而把从句放在后面; That the earth turns around the sun is known to all.It is known to all that the earth turns around the sun./ thathe said at the meeting surprised us. he turned up at the meeting surprised us.2. if / whether _______you go or stay at home won’t make any differences.What a pity _____is _____you didn’t arrive by daylight.A. there, becauseB. it, thatC. he, whenD. that, formatter how/who/what/where/whenWe are ready to do ______ the country wants us to do.A. whatB. whichC. no matter whatD. whateveris a pity that you should miss such a good chance.___ he made an important speech at the meeting was true.A. ThatB. WhyC. WhatD. How6. ___we’ll go camping tomorrow depends on the weather .A IfB WhetherC ThatD Whereis known to us all is that America is a developed country .A WhichB AsC WhatD It8. It’s known to us all ___ a form of energy .A. water isB. that water isC. is waterD. that water to9. It worried her a bit ___ her hair was turning gray.A. whetherB. thatC. whatD. whenI say and think ___ none of your business.A. isB. areC. has D have11. ____ his dream of going to college will come true is uncertain.That B. Whether C. If D. Even if12. It is known to us ___ where there is pollution, there is harm.A. whichB. whereC. whatD. that13. --- I saw your neighbor break your window with a basketball.--- ____ it made me nearly mad.A. That he brokeB. What he brokeC. He brokeD. His break remains a question ____ we can get so much money in such a short time.B. thatC. whenD. what15. He made a promise ___ anyone set him free he would make him very rich.A. thatB. ifC. whatD. that if16. They lost their way in the forest and ____ made matters worse was ___ night began to fall.A. what; thatB. it; thatC. what; whenD. which; what17. ________that they found an unusual plant in the forest.A. It is saidB. They are saidC. It saidD. It says18. _____ caused the accident is still a complete mystery.A. WhatB. ThatC. HowD. Where19. It worried Mary a lot _____ she would pass the college entrance examination.A. whetherB. ifC. thatD. how20. ____ is no possibility ______ Bob will win the first prize in the match.A. There, thatB. It, thatC. There, whetherD. It, whether21. ____surprised me most was _____such a little girl of seven could play the violin so well.A. That; whatB. What; thatC. That; thatD. What; what22. _____ helped to save the drowning girl is worth praising.A. WhoB. AnyoneC. WhoeverD. The person23. ____ she couldn’t understand was _____ fewer and fewer students showed interest in her lessons.A. What; whyB. That; whyC. What; becauseD. Why; that24. It was ____ he said ___ disappointed me.A. What; thatB. That; thatC. What; whatD. That;what25. ___ is a fact that English is being accepted as an international language.A. ThereB. ThisC. ThatD. It26. ______leaves the room last ought to turn off the lights.A. AnyoneB. The personC. WhoeverD. Whomakes mistakes must correct them. A. What B. That C. Whoever D. Whatever28. Is this factory you visited the other dayA. thatB. whereC. in whichD. the oneand why he came here ________ yet.A. is not knownB. are not knownC. has not knownD. have not known30. ________ is no reason for dismissing her.A. Because she was a few minutes lateB. Owing to a few minutes lateC. The fact that she was a few minutes lateD. Being a few minutes late31. ________ Tom liked to eat was different from ________.A. That…that you had expectedB. What …that you had expectedC. That…what you had expectedD. What…what you had expectedwe go swimming every day ________ us a lot of good.A. If...doB. That...doC. If...doesD. That...does________ Bob drives badly.A. thinks thatB. is thought whatC. thought thatD. is thought that34.It's uncertain ________ the experiment is worth doing.A. ifB. thatC. whetherD. howthe boy didn't take medicine made his mother angry.A. ThatB. WhatC. HowD. Whichwe can't get seems better than ____ we have.A. What, whatB. What, thatC. That, thatD. That, what37.____ you don't like him is none of my business.A. WhatB. WhoC. ThatD. Whether38..____ we'll go camping tomorrow depends on the weather.A. IfB. WhetherC. ThatD. Wheregoing to do the job will be decided by the Party committee.A. ThatB. WhyC. HowD. Who'll finish translating the book depends on the . When B. Why C. What D. Thatwon't go there is clear to all of . How B. What C. Why D. Thishouse will be built will be discussed at tomorrow's meeting.A. IfB. WhereC. ThatD. What43_______you come or not is up to you. A. What B. If C. Why D. Whetherwill win the match is a matter of public concern.A. WhichB. ThatC. IfD. How45 Is this the factory ___ some foreign friends visited other dayA thatB whereC whichD the one46 Is this the factory ___ he worked ten years agoA thatB whereC whichD the one1. what / that2. Whether 3--10 BDA BCBBA 11--20 BDAAD AAAAA 21--30 BCAAD CCACC 31--40 DDDCA ACBDA 41--46 CBDAAB。

主语从句讲解及其练习

主语从句一、主语从句的连词分三类（1）从属连词引导的主语从句（that whether if）that引导的主语从句:引导词that无含义/在句中不做成分/不可以省。

That 引导主语从句通常用it 作形式主语。

例如：That you will win the medal seems unlikely.That she survived the accident is a miracle.whether 引导的主语从句: whether有含义(是否)/在句中不做成分/不可以省。

注意：引导主语从句，不能用if不能在开头，只能用whether。

Whether we will hold a party in the open air tomorrow depends on the weather. Whether she is coming or not doesn’t matter too much.（2）用连接代词引导的主语从句在由连接代词who, whose, whom, which, what, whoever, whomever, whichever, whatever引导的名词性从句中，其连接代词在句中起名词性作用，担当一定成分. 例如：What you need is more practice.Whatever we do is to serve the people.注：whatever / whoever的功用whatever, whoever在主语从句中不含疑问意义。

它引导主语从句，并在从句中作主语、宾语、表语等。

whatever = anything that; whoever = anyone who。

要注意和whatever, whoever引导的让步状语从句的区别。

主语从句讲解

主语从句主语从句：在复合句中作主语的句子。

主语从句的引导词主要有连词that, whether, if连接代词what, who, whom, whose，which, whatever, whoever, whichever等。

连接副词when，where，how, why1. that 引导的主语从句that 引导的主语从句一般位于句首，有时也用it作形式主语而把that从句后置。

that 在从句中不作任何成分，也没有实际意义，只起连接作用。

（从句位于句首时that不可省略，从句位于句末一般不能省略，在口语中偶尔可以省略）Eg: That he will come is certain.That China is a great socialist country is well known.It has been decided (that)they should start the project the next month.他们决定下个月开始这项工程2.whether/if 引导的主语从句whether/if 只起连接作用，有词义，是“是否”的意思。

whether 引导的主语从句可置于句首，这时不能用if 代替；if 引导的主语从句只能用it作形式主语，而把从句放在句末。

Eg: Whether he will be able to come is still a question.Whether the work can be completed on time is doubtful.=It is doubtful whether/if the work can be completed on time 这项工作能否按时完成还不确定。

3.连接代词和连接副词引导的主语从句连接代词和连接副词引导的主语从句要在句中作一定的成分（主语、宾语、表语、定语、状语、补语等），它们有一定的词义。

并且在任何情况下都不能省略。

选择性必修一Unit5重点语法：主语从句

选择性必修一Unit5重点语法：主语从句【课中讲解】在句子中起主语作用的从句称为主语从句。

1.主语从句主要有四类（1）由连词that引导的主语从句:引导词that无含义/在句中不做成分/不可以省.例如：That you will win the medal seems unlikely.That you are so indifferent bothers me.That she survived the accident is a miracle.（2）用连词whether 引导的主语从句: whether有含义(是否)/在句中不做成分/不可以省.注：引导主语从句, 不能用if, 只能用whether.例如：Whether we will hold a party in the open air tomorrow depends on the weather.（3）用连接代词引导的主语从句在由连接代词who, whose, whom, which, what, whoever, whomever, whichever, whatever引导的名词性从句中,其连接代词在句中起名词性作用, 担当一定成分.例如：What you need is more practice. What I want to know is this.Whatever we do is to serve the people.注：whatever / whoever的功用whatever, whoever在主语从句中不含疑问意义.它引导主语从句, 并在从句中作主语、宾语、表语等.whatever = anything that; whoever = anyone who.要注意和whatever, whoever引导的让步状语从句的区别.Whoever breaks the law should be punished. （主语从句）（＝Anyone who breaks the law should be punished. ）Whoever breaks the law, he should be punished. （让步状语从句）（＝No matter who breaks the law, he should be punished. ）（4）用连接副词when, where, why, how引导名词性从句(其连接副词有含义,在句中作状语.)例如:Where we should leave it is a problem.2.注意点: it构成的主语从句（1）由连词that引导的主语从句, 在多数情况下放到句子的后面, 而用代词it作形式主语.例如：That light travels in straight lines is known to all.=It is known to all that light travels in straight lines.When the plane is to take off has not been announced.= It has not been announced when the plane is to take off.(但当what引导的主语从句表示“…的东西”时, 一般不用it作形式主语.)错:It is a book what he wants.对:What he wants is a book.另外, 需要注意的是, it作形式主语代替主语从句时, 要注意和as引导的定语从句的区别.试比较：It was reported that the US was under the terrorist attack.As was reported, the US was under the terrorist attack.（2）常见用it作形式主语的复合句结构A. It is +名词+从句It is a fact that…事实是……It is good news that ………是好消息It is a question that ………是个问题It is mon knowledge that ………是常识类似的名词还有：a pity；a wonder；a good thing；no wonder；surprise等.例如：It is a mystery to me how it all happened.It is mon knowledge that the whale is not a fish.It is no surprise that Bob should have won the game.It’s a pity that you missed the film.B. It is +形容词+从句It is necessary that …有必要……It is clear that …很清楚……It is likely that …很可能……It is important that …重要的是……类似的形容词还有：Strange; natural; obvious; true; good; wonderful; possible; unlikely; quite;unusual; certain; evident; worth-while; surprising; interesting; astonishing, etc.例如：It is doubtful whether she will be able to e.It was really astonishing that he refused to talk to you.It is essential that he should be here by the weekend.It seems obvious that we cannot go on like this.It is necessary that you （should）master the language.It is important that a student learn English well.It is likely that a hurricane will arrive soon.需要注意的是, 这类主语从句中, 谓语动词很多为“（should）＋动词原形”, 即要用虚拟语气.C. It is +过去分词+从句It is said that …据说……It is reported that …据报道……It has been proved that …已证明……It must be proved that…必须指出……类似的过去分词还有：known; estimated; expected; believed; thought; hoped; noted; discussed; required;decided; suggested; demanded; made clear; found out, etc.例如：It is thought that he is the best player.It is estimated that the vase is 2000 years old.It is used to be thought that a new star must be due to a collision between two stars.It has not been made clear when the new road is to be opened to traffic.It is said that he was killed in the earthquake.D. It happened / doesn’t matter / makes no difference / occurred …that …It makes no difference whether he will attend the meeting or not.It does not matter if I missed my train.It happened that I saw him yesterday.【过关检测】1.____________you said at the meeting describes a bright future for the company. （2013四川）A. WhenB. HowC. WhatD. That【答案】C【解析】这里what在从句中充当宾语，指物，无范围。

主语从句讲解及其练习

主语从句一、主语从句的连词分三类（ 1）隶属连词引导的主语从句（ that whether if ）that 引导的主语从句 :引导词 that 无含义 /在句中不做成分 /不能够够省。

That 引导主语从句平时用 it 作形式主语。

比方： That you will win the medal seems unlikely.That she survived the accident is a miracle.whether 引导的主语从句 :whether 有含义 (可否 )/在句中不做成分 /不能够够省。

注意：引导主语从句，不能够用 if 不能够在开头，只能用w hether。

Whether we will hold a party in the open air tomorrow depends on the weather. Whether she is coming or notdoesn’t matter too much.（ 2）用连接代词引导的主语从句在由连接代词 who, whose, whom, which, what, whoever, whomever, whichever, whatever 引导的名词性从句中，其连接代词在句中起名词性作用，担当必然成分.比方： What you need is more practice.Whatever we do is to serve the people.注： whatever / whoever的功用whatever, whoever在主语从句中不含疑问意义。

它引导主语从句，并在从句中作主语、宾语、表语等。

whatever = anything that; whoever = anyone who。

要注意和 whatever, whoever引导的退步状语从句的差异。

如： Whoever breaks the law should be punished.（主语从句）（＝ Anyone who breaks the law should be punished.）Whoever breaks the law, he should be punished（.退步状语从句）（＝ No matter who breaks the law, he should be punished）.（ 3）用连接副词 when, where, why, how 引导的名词性从句 (其连接副词有含义 , 在句中作状语。

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