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.引导主语从句的关联词有三类：
(1)从属连词that，whether
That they were true sisters was clear from the facial resemblance between them.
Whether he’ll come here isn’t clea
r.
(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, why
2.主语从句是在复合句中充当主语的从句，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。
结构中的主语从句不可提前。
(2) It is said , (reported) …
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.
结构中的主语从句不可提前。
(4) It doesn’t matter how/whether …
例如：It doesn’t matter whether he is wr ong 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?
3.主语从句用陈述语序。关联词位于句首不能省略。
How he became a great scientist is known to us all.
That he finished writing the composition in such a short time surprised us all.
4.主语从句中注意的事项：
1）在主语从句中，谓语动词一般用单数。
Whatever he says is of no importance.
Whoever says this is wrong.
但谓语动词用单数还是复数，不可一概而论，而要视句子的意义而定
What I need is money.
What I need are books.
2）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。What you said yesterday is right.
That she is still alive is a consolation.
3）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。而it 引导的强调句则是对句子某一部分进行强调，无论强调的是什么成分，都可用连词that。被强调部分指人是也可用who/whom。
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.
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。
It is still a mystery what caused the accident.
It is a mystery that his death remained.
4) whether与if
whether引导主语从句时,常置于句首(此时whether不能用if代替),也有后移的用法(此时whether可以用if代替)
Whether they will come is not yet known.
It is not yet known whether / if they will go there.
whether和if的区别还有：
1.引导表语从句用whether
The question is whether you should accept it.
2. whether可以引导从句作介词的宾语
I’m not interested in whether they’ll go or not.
It depends on whether we have got enough money.
3. whether可以直接跟动词不定式连用
I didn’t know whether to laugh or to cry.
She hasn’t decided whether to go or not.
5）用it作形式主语的结构
(1) It is ＋名词＋从句
非常荣幸
事实是… It is an honor that …
It is a fact that …
是常识
It is common knowledge that …
(2) It is ＋形容词＋从句
奇怪的是…
It is natural that…
很自然It is strange that…
(3) It is ＋不及物动词＋从句
It seems that… 似乎… It happened that… 碰巧…
似乎…
It appears that…
(4) It ＋过去分词＋从句
已证实…
It is reported that…
据报道… It has been proved that…
据说…
It is said that…
名词性从句之主语从句讲解
名词性从句---主语从句 1. What is needed for the space trip is careful preparation. 2. Her wish is that she can lose weight soon. 3. I think that woman can reach every high achievements in many fields of science. 4. We were very excited at the news that our team had won. 引导名词性从句的关联词可分为三类： 一．从属连词：that（无任何词意） whether, if（均表示“是否”表明从句内容的不确定性） as if ,as though（均表示“好像”，“似乎”）以上在从句中均不充当任何成分二．连接代词：what, who, whom, which，whose, whatever, whoever, whichever(作主宾表定) 三．连接副词：when, where, how, why(作状语) I.主语从句 1.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。 2.位置：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。 3.引导主语从句的关联词： (1)从属连词that,whether,if (在从句中不充当成分，仅起连接作用) That Jack won the match yesterday surprised us. Whether he’ll come here isn’t clear. (此处不能用if) (2)连接代词who, whom, whose, what, which, whoever, whatever, whichever(充当主宾表定) What she did is not known. Whoever comes is welcome. (3)连接副词where,when,how,why(在从句中充当状语) How this happened is not clear to anyone. When the meeting will be held is decided by our manager. 4.有时为了避免头重脚轻，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. = It depends on its author how the book will sell. That he is the best student in the class is obvious. = It is obvious that he is the best student in the class. 用it作形式主语的几种常见结构： (1) It is ＋名词＋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＋从句 It is natural that… 很自然It is strange that… 奇怪的是… (3) It is ＋不及物动词＋从句 It seems that… 似乎… It happened that… 碰巧… It ap pears that… 似乎… (4) It ＋过去分词＋从句
主语从句和强调句造句
主语从句造句： 1.How well the prediction will be validated by later performance depends upon the amount and reliability of the information used. 这些预测以后将在多大程度上被之后的表现证实，取决于所采用信息的数量和可靠性。 2.It is often important that you make it clear what your particular role is at a given time. 你要搞清楚在指定时期内你的特定角色是什么，这很重要。 3.It is reported that the unemployment rate is very high in many developed countries because financial crisis. 据报道，由于金融危机，很多发达国家的失业率都很高。 4.That mental health is important to physical condition is a fact. 精神健康对身体状况很重要，这是一个事实。 5.That he finished writing the composition in such a short time surprised us all. 他在这么短的时间内完成了写作使我们所有人都惊讶。 6.Whether we will go for an outing tomorrow remains unknown. 我们明天是否会去远足有待商榷。 7.What make the river more beautiful are the plants growing in the water. 为河水增色的是水里的荷花。 8.What struck me was that they have all suffered a lot. 给我印象深刻的是他们都受过很多苦。 9.Whether we will hold a party in the open air tomorrow depends on the weather. 我们明天是否在户外开晚会要看天气而定。 10.Which car you will choose to buy makes no difference. 你决定买哪一辆车都不会有任何区别。 11.It is common knowledge that honesty is the best policy. 诚实是最好的政策是共识。 12.What they need most is not financial aid or loan but advanced technologies and talents in certain key areas.
主语从句详解及练习-附答案
语法要点剖析 一、名词性从句 主语从句、表语从句、宾语从句、同位语从句，在整个句子中所起的作用，相当于一个名词。因此，这四种从句通称为名词性从句。 引导名词性从句的连接词可分为三类： 连接词：that, whether, if （不充当从句的任何成分） 连接代词：what, whatever, who, whoever, whom, whose, which. 连接副词：when, where, how, why 1. 主语从句 作句子主语的从句叫主语从句。主语从句通常由从属连词that，whether，if 和连接代词what，who，which，whatever，whoever以及连接副词how，when，where，why等词引导。that在句中无词义，只起连接作用；连接代词和连接副 词在句中既保留自己的疑问含义、又起连接作用，在从句中充当从句的成分。例如： What he wants to tell us is not clear. 他要跟我们说什么，还不清楚。 It is known to us how he became a writer. 我们都知道他是如何成为一名 作家的。 Where the English evening will be held has not yet been announced. 英语晚会将在哪里举行，还没有宣布。 有时为避免句子头重脚轻，常用形式主语it代替主语从句作形式主语放于句首，而把主语从句置于句末。主语从句后的谓语动词一般用单数形式。常用句型如下： （1）It + be + 名词+ that从句（2）It + be + 形容词+ that从句 （3）It + be + 动词的过去分词+ that从句（4）It + 不及物动词+ that 从句 另注意在主语从句中用来表示惊奇、不相信、惋惜、理应如此等语气时，谓语动词要用虚拟语气“(should) +do”，常用的句型有： It is necessary (important, natural, strange, etc.) that … It is a pity (a shame, no wonder, etc.) that… It is suggested (requested, proposed, desired, etc.) that… 2. 宾语从句 名词句用作宾语的从句叫宾语从句。引导宾语从句的关联词与引导主语从句表语从句的关联词大致一样，在句中可以作谓语动词或介词及非谓语动词的宾语。 1. 由连接词that引导的宾语从句 由连接词that引导宾语从句时，that在句中不担任任何成分，在口语或非正式的文体中常被省去，但如从句是并列句时,第二个分句前的that不可省。例如：He has told me that he will go to Shanghai tomorrow.他已经告诉我他明天要去 上海。 We must never think (that) we are good in everything while others are good in nothing. 我们决不能认为自己什么都好，别人什么都不好。
各类从句讲解与例句
英语中六大从句用法总结 1.主语从句 1）主语从句可直接位于主语的位置，如果从句较长，谓语又较短，可用it作形式主语，而将从句放在句末。常见的句型有： *It is a fact\a pity\a question\good news that... *It seems\appears\happened\has turned out that... *It is clear\important\likely\possible that... *It is said\reported\estimated\has been proved that... It is said that comic books create a connection between people of the same generation. It seems that the performance is very useful. 2)what引导的主语从句表示“...的东西时”，一般不用it作形式主语。 What we lack is experience. 3)what,who,when,why,whether等词含有各自的疑问意义，但它们引导的主语从句，都用陈述语序。 How the plan is to be carried out should be discussed again. I did know why I felt like crying. 2.宾语从句 1）宾语从句可位于及物动词、介词和某些形容词后。连词that常可省略。介词后一般接疑问词引导的宾语从句。in that(因为),except that(除了),but that(只是）已构成固定搭配，其他介词后一般不接that引导的宾语从句。 *I promised that I would change the situation. *All this is different from what American young people would say about friendship. *He is certain that watching so much television is not good for children. *This article is well-written except that it is a bit too long. 2）非谓语动词之后的宾语从句 Reading that it was just a difference in custom, the foreigner smiled and said nothing. 这个外国人知道了这只是风俗的不同后，就笑了笑，没说什么。 On being asked whether he had any good food in Germany, he answered ”Terrible”. 一问到他在德国是否吃过什么好菜，他就回答说：“糟糕的很”。 3)宾语从句后如有宾补，要用形式宾语it来代替，而把宾语从句移至宾补之后。 He has made it clear that he would not change his mind. 4)在think,believe,suppose,expect等动词后的宾语从句中，如果谓语是否定的，一般将否定词移至主句谓语上，宾语从句则变成肯定形式。 He didn't think that the money was well spent. 3.表语从句 表语从句出现在结构为“主语+系动词+表语从句”的句子中。表语从句除可用that,what,when,why,whether,how 等引导外，还可由because,as if(though)等引导。不缺其他成分时，用that引导，且不可省略。如主句主语为reason,只能用that引导表语从句，不可用because. Perhaps the most important thing to remember is that there is no one common type of life in America. The reason why so many people died there is that there were not enough food supplies. It looks as if successful international cultural communication will make the world smaller. 4.同位语从句 同位语从句用于对前面出现的名词作进一步说明，一般用连词that引导，由于先行名词的意义不同，也可用whether,who,when,where,what,why,how等引导。常见的先行名词有fact,idea,belief,news,hope,conclusion,evidence,suggestion,order,problem,report,decision.有时由于谓语较短，将同位语从句位于谓语之后。 She finally made the decision that she would join the fashion show. I had no idea how many books I could borrow at a time. The news came that their team had won the championship.
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，whether 1）that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。2）whether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。 a.That 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. 1）What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. 2）whatever / 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: Whoever(Anyone who) wants to enter into this school must take the exam. Whatever(Anything 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。How this happened is not clear to anyone. 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 A. It + be + 形容词+ that 从句 (obvious, true, surprising, good, wonderful, funny, possible, likely, certain, probable, etc.) 如：It is certain that she will do well in her exam. B. It + be + 名词词组+ that 从句(an honour, a fact, a pity, 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’s a pity that we can’t go. 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 ,turn out）。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
英语主语从句
主语从句 （一）主语从句的标记主语从句通常由连词that和whether (if)、连接代词或连接副词以及关系代词型what引导。 1. that引导 That he is still alive is a wonder. 他还活着，真是奇迹。 That we shall be late is certain. 我们要晚了，这是确定无疑的。 That he should have ignored the working class was natural. 他忽视工人阶级是很自然的。That she is still alive is a consolation. 她还活着是使人感到宽慰的。 That she became an artist may have been due to her father’s influence. 她成为画家可能是受她父亲的影响。 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。 That she was chosen made a tremendous stir in her village. 她被挑选上，在她村子里引起很大轰动。 2. whether引导 Whether it will do us harm remains to be seen. 是否对我们有害还要看一看。 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 Whoever (=anyone who) fails to see this will make a big blunder. Whatever(=anything that) she did was reasonable. 无论什么 Anything that she did was reasonable. Whichever (of you) comes in first will receive a prize. 无论(你们)谁先到都可以得奖。Whichever(=anything that) you want is yours. 你要哪个哪个就是你的。 What do you need? What you need is a good rest. I don’t know what you need? 4. 连接副词引导 When we arrive doesn’t matter. 什么时候到没有关系。 When do we arrive? How it was done was a mystery. 这是怎样做的是一个谜。 How was it done? How this happened is not clear to anyone. 这件事怎样发生的，谁也不清楚。 How did this happen? How many people we are to invite is still a question. 邀请多少人还是一个问题。How many people are we to invite? Where I spend my summer is no business of yours. 我在哪里过暑假不关你的事。 Where do i spend my summer? 5. 连接代词型what引导 What(=the thing that) we need is money. 我们需要的是钱。What do we need? What I want to know is this. 我想知道的就是这一点。What’s done is done. 事已成定局。 What=the thing that he says is not important. 他说的话并不重要。What does he say? What I am telling you is mere impressions. 我和你说的都不过是一些印象而已。What make the river more beautiful are the lotus plants growing in the water. 为河水增色的是水里的荷花。What you need is a good-sized canvas bag. 你需要的是一个比较大的帆布袋。 What I am afraid of is their taking him to Portugal. 我担心的是他们把他带到葡萄牙去。What struck me was that they have all suffered a lot. 给我很深印象的是他们都受过很多苦。（二）
高考英语专项复习主语从句详解
主语从句详解 一、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. 注意：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. Whether she is coming or not doesn’t matter too much. （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
主语从句例句
主语从句 1.That he is still alive is a wonder. 2.That we shall be late is certain. 3.That he should have ignored the working class was natural. 4.That she is still alive is a consolation. 5.That she became an artist may have been due to her father's influence. 6.That you are coming to London is the best news I have heard this long time. 7.That she was chosen made a tremendous stir in her village. 8.Whether it will do us harm remains to be seen. 9.Whether they would support us was a problem. 10.Whoever is top from wins the game when two matched players meet. 11.Whichever (of you) comes in first will receive a prize. 12.Whichever you want is yours. 13.When we arrive doesn't matter. 14.How it was done was a mystery. 15.How this happened is not clear to anyone. 16.How many people we are to invite is still a question. 17.Where I spend my summer is no business of yours. 18.What we need is money. 19.What I want to know is this. 20.What's done is done. 21.What he says is not important. 22.What I am telling you is mere impressions. 23.What make the river more beautiful are the lotus plants growing in the water. 24.What you need is a good-sized canvas bag. 25.What I am afraid of is their taking him to Portugal. 26.What struck me was that they have all suffered a lot. 27.It's a pity that he didn't come. 28.It is important that he should know about this. 29.It's vital that we be present. 30.It was intended that you be the candidate. 31.It is important that this mission not fail. 32.It is essential that a meeting be convened this week. 33.It is appropriate that this tax be abolished. 34.It's unfair that so many people should lose their jobs. 35.It's amazing that she should have said nothing about it. 36.It's unthinkable that they should deny my request. 37.That they should refuse to sign the petition required great courage. 38.Whether they would support us was a problem. 39.It was a problem whether they would support us. 40.It remains to be seen whether it will do us harm or good. 41.What we need is money. 42.What I want to know is this.
高中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。) 例如:Where we should leave it is a problem. When they will come hasn’t been made pubic.
主语从句例句
主语从句 一、翻译下列句子 1.That he is still alive is a wonder. 2.That we shall be late is certain. 3.That he should have ignored the working class was natural. 4.That you are coming to London is the best news 5.Whether it will do us harm remains to be seen. 6.Whether they would support us was a problem. 7.Whether they would support us was a problem. 8.When we arrive doesn't matter. 9.When we shall hold our sports meet is not decided. 10.How it was done was a secret 11.How this happened is not clear to anyone. 12.How many people we are to invite is still a question. 13.Where I spend my summer is no business of yours. 14.What we need is money. 15.What I want to know is this. 16.What he says is not important. 17.What make the river more beautiful are the lotus plants growing in the water. 18.What struck me was that they have all suffered a lot. 19.It's a pity that he didn't come. 20.It is important that he should know about this. 21.It's unfair that so many people should lose their jobs. 22.It's amazing that she should have said nothing about it. 23.It's unthinkable that they should deny my request. 24.It seems that you are right. 25.It was clear his words pleased her. 26.It doesn’t matter much where we live. 27.It was a problem whether they would support us. 28.It remains to be seen whether it will do us harm or good. 29.It is said that he’s got married. 30.It is believed that he will win the match. 31.It is reported that Chinese team got 102 golden medals. 32.Whoever pollutes the environment should be punished. 33.Whatever he did was right.
主语从句详解及练习_附答案
高二年级语法要点剖析（李翌洋） 一、名词性从句 主语从句、表语从句、宾语从句、同位语从句，在整个句子中所起的作用，相当于一个名词。因此，这四种从句通称为名词性从句。 引导名词性从句的连接词可分为三类： 连接词：that, whether, if （不充当从句的任何成分） 连接代词：what, whatever, who, whoever, whom, whose, which. 连接副词：when, where, how, why 1. 主语从句 作句子主语的从句叫主语从句。主语从句通常由从属连词that，whether，if 和连接代词what，who，which，whatever，whoever以及连接副词how，when，where，why等词引导。that在句中无词义，只起连接作用；连接代词和连接副词在句中既保留自己的疑问含义、又起连接作用，在从句中充当从句的成分。 例如： （1）What he wants to tell us is not clear. 他要跟我们说什么，还不清楚。 It is known to us how he became a writer. 我们都知道他是如何成为一名作家的。 Where the English evening will be held has not yet been announced. 英语晚会将在哪里举行，还没有宣布。 注意：有时为避免句子头重脚轻，常用形式主语it代替主语从句作形式主语放于句首，而把主语从句置于句末。主语从句后的谓语动词一般用单数形式。常用句型如下： （1）It + be + 名词+ that从句 （2）It + be + 形容词+ that从句 （3）It + be + 动词的过去分词+ that从句 （4）It + 不及物动词+ that 从句 另注意在主语从句中用来表示惊奇、不相信、惋惜、理应如此等语气时，谓语动词要用虚拟语气“(should) +do”，常用的句型有： It is necessary (important, natural, strange, etc.) that … It is a pity (a shame, no wonder, etc.) that… It is suggested (requested, proposed, desired, etc.) that…
高中英语语法主语从句讲解及练习
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.