主语从句
高中英语知识点讲义
----主语从句
一、教学目标
1.知识目标：掌握主语从句的基本意义、形式，以及连接词的用法。
2.能力目标：会选定连接词，会运用主语从句进行口语或书面表达。
3. 情绪和态度目标：坚定学生学习英语语法的信心，从而激发学习英语语法的
学习兴趣。
二、教学重难点
1. 主语从句的连接词的选定。
2. 主语从句遵循的特点：陈述语气、缺什么补什么、不缺补that。
3. it做形式主语的情况。
三、教学步骤
1、首先，我们来看下面几个例子，请大家找出划线部分词语在句子中所做的成
分。
（1）Jeremy Lin is a basketball player.
（2）Smoking is bad for you.
（3）To find your way can be a problem.
（4）This is not funny at all.
2. 主语从句
（一）定义：顾名思义，用作主语的从句就叫做主语从句。它是名词性从句的一种。
（注意：名词性从句分为：主语从句、表语从句、宾语从句和同位语从句。）
（二）请看下面两个例子，大家便会对主语从句有一个初步概念。
A. The story makes me laugh. (词组)
B. That he failed the test makes me laugh.（从句）
（三）引导主语从句的连接词
连词：that/ whether
连接代词：who/ what/ which (在主语从句中做主语、宾语、表语、定语等) 连接副词：when/ where/ how/ why（在主语从句中做状语）
（即：7个wh-, 1个that, 1个how）
3. 连接词的用法
（一）that
That作为从属连词引导主语从句时，其本身没有实际意义，只起到引导作用，也不充当从句的任何成分，但不能省略。
如：That she left him made him heart-broken.
That you missed the film is really a pity.
注意：为了防止句子头重脚轻，通常把形式主语it放在主语位置，真正的主语搁置于末尾。常用的句型有：
（1）It + 系动词 + adj. + that从句
常在此句式中的形容词有ture, certain, important, wonderful, funny, possible, natural, obvious, clear, strange, wrong, right, likely, probable等。而且，此句式中主语从句的谓语动词常用“should+动词原形”的形式，其中should可省略。
如：It is obvious that the manager of the coffee shop was waiting for Li Fang to leave.
高中英语语法主语从句 第一节主语从句 1．考点解析。 1．主语从句一般分为三类：由what等代词引导的主语从句；由连词that 引导主语从句，多数情况下由it作形式主语，that从句放到句子后面去；由连接代词或连接副词（或whether）引导的主语从句。 What they are after is beauty. It is not your fault that we can’t arrive on time. When they will arrive has not been decided. 2. 由关系代词what引导的主语从句，也可由whatever（“所…的一切”）或 whoever（“一切…的人”）引导。 Whatever he wants is your support. Whoever comes will be welcome. 3. 大多数主语从句都可用it代替，作形式主语，把主语从句放在句尾。要注意it代替主语从句和it引导的强调句的区别。强调句的结构是it is/was….+that…，强调人是可把that 换做who，whom，whose。如强调的是状语时，也只能用that,而不能用when, where, how, why等。 It was in Paris that they fell in love with each other. It is the lady who was my English teacher. It was last semester that he won the first prize. 2. 试题详解。 1．______ he needs is more experience. A. Who B. That C. What D. How 2.It was because of the heavy snow ______ the train was late. A. why B. that C. so D. thus 3．It doesn’t matter ______ he likes or not. A. whether B. what C. when D. that 4______ he has won the Noble Prize has been proved to be true. A. What B. How C. It D. That 5．What he wants _______ to sleep more. A. are B. have been C. is D. were 6．______ we can begin this investigation is still a question. A. When B. Why C. What D. That 7．It is ______ that the highway will be open to traffic nest year. A. report B. reported C. reporting D. by report 8．______ fails to see this will make a big mistake. A. Whatever B. what C. wherever D. Whoever 9．It is a mystery _____ the prisoner escaped. A. why B. how C. what D. that 10．It was last summer _____ he graduated from the college. A. that B. when C. / D. where 3. 实战演练。 1. We didn’t know ______ she didn’t come. A. why B. that C. when D. it 2. It is still doubtful _______ she would play the part.
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.
高一年级必修三名词性从句语法专题（一） 主语从句（Noun Clauses as the Subject）I．Revision What part does the underlined part serve as in each sentence? A tree has fallen across the road. ____________ Y ou are a student. ____________ To find your way can be a problem. ____________ Smoking is bad for you. ____________ “How do you do?” is a greeting. ____________ What she said is not yet known. ____________ That we shall be late is certain. ____________ It is certain that we shall be late. ____________ II．Learning subjective clauses Step 1划出主语从句, 初步识别主语从句 How you got me blind is still a mystery. That she had won the first prize made the girl very happy. When and where we will hold the meeting hasn’t been decided. Whether we go by train or by boat makes no difference. Who will host the meeting is still a serious problem. Whoever comes to China is welcome.. Step 2 看以下的主语从句，总结主语从句的位置特点。 阅读第四单元的课文，分析下列文中的主语从句，并进行小组讨论。 1.What it was to become was uncertain until between 4.5 and 3.8 billion years ago. 2.What is even more important is that as the earth cooled down, water began to appear on its surface. 3.What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acids into the oceans and seas. 4.Why they suddenly disappeared still remains a mystery. 5.So whether life will continue on the earth for millions of years to come will depend on whether this problem will be solved. 先划分句子，归纳出主语从句所在的位置， 根据以上主语从句实例，_____________________________________ Step 3 学习主语从句的主要连接词 1）从属连词：that，whether
xx考研英语语法复习主语从句 在复合句中充当主语成分的句子叫作主语从句。具体形式为：引导词引导一个从句作主语;或者it作形式主语+谓语/系表结构+引导词+从句。 ⑴陈述句充当主语从句，连词为that(that没有实际含义，在从句中只起连接作用，不在从句中作任何语法成分)，从句为"that+陈述句"，that不能省略。 【例句】 That Chris Lee won the champion of Super Girl in xx arouse wide public concern. 李宇春赢得xx年超女冠军这件事引起了社会的广泛关注。 ⑵一般疑问句充当主语从句，连词为whether(whether"是否"的含义，在从句中只起连接作用，不在从句中作任何语法成分)，从句为"whether+陈述句语序"，whether不能省略。 【例句】 Whether this is true or not remains a mystery. 这是对是错还是个谜。 ⑶特殊疑问句充当主语从句，连词为特殊疑问词(特殊疑问词都有自己的含义，在从句中作一定的语法成分)，从句为"特殊疑问词+陈述句语序"，特殊疑问词不能省略。 【例句】 例1 --what
What caused the aident remains unknown. 是什么引起了这一事故仍然。 例2--where Where my wife and I should enjoy our honeymoon is still unsettled. 我太太和我应该去哪享受我们的蜜月还没有最后决定。 例3 --which Which university I should choose to continue my further education is a question of great importance. 我应该考哪个大学的研究生是个很重要的问题。 例4--when When and where the test will be given is not yet decided. 什么时候在什么地方进行考试还没定下来。 例5---ever Whoever gets the job will have a lot of work to do. 任何得到这份工作的人都将要有很多工作要做。 例6--how How we can protect the grain from damp needs to be discussed. 我们怎样才能保护粮食不受潮需要讨论讨论。 3.It句型
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.
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）
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。 That she survived the accident is a miracle. 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 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Whatever we do is to serve the people. 注：whatever / whoever的功用 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.
Subject Clause and Predicative Clause Ⅰ. 主语从句(Subject Clause) 一定义：__________________________________________________. 1. He is right . 2. What he said is right . 二.主语从句引导词 1.主语从句的引导词与宾语从句相同。（但不用if （是否），只能用whether(是否)） 1) that 2) whether 3) what , which ,who, whom, whose, whatever , whichever..... 4) where , when , why, how, wherever, whenever ..... 5) how many , what color, how far等。 2. 引导主语从句的关联词除起连接句子的作用，绝大多数关联词在主从中要充 当一定的句子成分。 3. 主语从句的语序是：关联词+S+V 三. 主语从句引导词的用法: 1. that 的用法：that 引导句意完整, 意义明确不缺成分的陈述句；无词义，在 主从中不充当句子成分，不能省略。 仿照例子改写句子改成相应的主语从句 Model: There is life on another planet (在另外的星球上) （that 引导的主从）It is almost impossible. →That there is life on another planet is almost impossible (主从) s v. 1). The scientist will give us a lecture next week. It is true. → 2). You don’t like him. It is none of my business.(不关我的事) → 3).Her hair was turning gray(灰色). It worried her bit. → 4). He told her everything. It is probable. → 5). He sings so well. It is no surprise. → 2. whether 的用法: whether引导的主从不缺句子成分，句意不完整，表达一种不确定，不明确的概念；whether当"是否"讲，在主从中不充当句子成分。Model: 由whether 引导的主从，相当于一般疑问句的作用。 Will I accept the gift ? It is none of your business. →Whether I accept the gift is none of your business. (主从) s v 1). Will our football team win? It is uncertain yet. → 2). Will the sports meet be held? It depends on the weather.
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 matt er 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 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. When they will come hasn’t been made pubic. 三、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.
（新人教版）2021版高考一轮英语复习 语法名词性从句导学案 考点一引导名词性从句的连接词 1.连接代词who,whose,whom,what,which及wh-ever等 它们有词义,在从句中作成分。what∕whatever指物,作主语、宾语、定语、表语;who∕whoever指人,在从句中作主语、宾语;whom∕whomever指人,在从句中作宾语;whose在从句中作定语;which∕whichever指人或物,在从句中作定语、主语、宾语。带-ever的连接词意义上有“任何……”之意。 What I want to know is the price of the bike. 我想知道的就是自行车的价格。 You can buy whatever you need in the shop. 在这家商店你能买到任何你需要的东西。 whoever,whatever,wherever...等引导的从句不仅是句子的语气加强了,而且此类词引导的句子表示让步和泛指的概念,而who,what,where...等引导的句子表示具体的概念。如: What he said is right. 他所说的是对的。(特指他这次所说的事情) Whatever he said is right. 无论他说什么都是对的。 此处,whatever= anything what,表示泛指和让步,意为“无论他说什么”。 Who will do it is not decided. 谁去做这件事还没有确定。(指一次具体的动作) Whoever does it will be punished. 无论谁做了这件事,都要受到惩罚。 (此处特别强调“无论是谁”) wh-ever这类词引导名词性从句时,不能用no matter+who∕what∕which...代替。 2.连接副词when,where,why,how等 它们有词义,在句中作状语。when表时间,why表原因,where表地点,how表方式、程度。 This is why I came here. 这是我来这儿的原因。
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.
整体思维学习名词性从句导学案 语法学习的目的：提升理解语言的准确性和提高运用语言的准确性 整体思维学习方法：整体思维学习法是指从整体到细节的认识事物的过程。当我们已经知道事物的整体概况后，会使细节的掌握变得更加轻松。这就好比当我们认识了太阳系后，再认识太阳系中的每个行星如地球就轻松多了，因为我们已经从宏观上把握了它所处的整个体系。整体思维学习语法遵循从整体到细节的学习过程，先从整体上了解语法的家族、在英语句子中所处的地位，所具有的不同的功能和使用的语境，再针对每一项的功能进行强化操练和运用，达到掌握的目的。 语法学习的黄金法则：以句子和语篇为载体理解语法的形式、意义和功用、以句子和语篇为载体记忆语法的形式、意义和功能、以听、读、说、写为主要手段内化语法知识，提升语言的理解能力和运用能力。 学习目标Learning objectives： At the end of the learning , students will be able to: 1. know about the basic structure of English sentences. 2.know about the whole system/family of noun clauses 3.know about the functions of noun clauses 4. use noun clauses in context and real situations by doing some exercises. 5. learn about how to learn grammar. 语法学习的步骤： I.Preparation for learning grammar: 语法学习前的知识准备 Q：What is a noun clause? Q: How does it come? Q: Why do we have to use a noun clause? Q: What role does it play in an English sentence? Required knowledge for learning about noun clauses: 英语简单句的基本构造 1）主语+谓语+（宾语）（谓语动词是不及物动词时没有宾语） We have developed good study habits. We study hard. He went to shanghai for a meeting. 2) 主语+系动词+表语（系动词可以是：be, become, grow, get, remain, feel等等） I am a teacher. They are at home. We are eager for the approach of the winter holiday. The problem remains unsolved. 在此基本主干上，依据具体语境需要添加同位语、状语、定语、补语或插入语等附加成分。其中，同位语放在主语或宾语后面，进一步说明主语或宾语的信息，状语的位置可放在句首或句尾，或谓语的前后；定语的位置放在主语和宾语的前面或后面做前置定语和后置定语，补语放在主语或宾语后面做主补或宾补。我们可以用树状结构来表示英文句子的基本结构。
在句子中起名词作用的句子叫名词性从句。名词性从句的功能相当于名词词组，它在复合句中能担任主语、宾语、表语、同位语等，因此根据它在句中不同的语法功能，名词性从句又可分为主语从句、宾语从句、表语从句和同位语从句。今天我们就来重点讲一下其中的主语从句。 在复合句中充当主语成分的句子叫作主语从句。它的具体表现形式是：引导词引导一个从句作主语；或者it作形式主语+谓语/系表结构+引导词+从句。 【例1】that That Chris Lee won the champion of Super Girl in 2005 arouse wide public concern.李宇春赢得2005年超女冠军这件事引起了社会的广泛关注。 【例2】what What caused the accident remains unknown.是什么引起了这一事故仍然未知。 【例3】where Where my wife and I should choose to continue my further education is a question of great importance.我太太和我应该去哪享受我们的蜜月还没有最后决定。 【例4】which Which university I should choose to continue my further education is a question of great importance.我应该考哪个大学的研究生是个很重要的问题。 【例5】when When and where the test will be given is not yet decided.什么时候在什么地方进行考试还没定下来。 【例6】-ever Whoever gets the job will have a lot of work to do.任何得到这份工作的人都将要有很多工作要做。 【例7】how How we can protect the grain from damp needs to be discussed.我们怎样才能保护粮食不受潮需要讨论。 【例8】whether Whether this is true or not remains a mystery.这是对是错还是个谜。 It句型 有的时候主语从句过长，根据人类短暂记忆规律，主语过长会影响理解和阅读，往往会用it作形式主语，而把真正的主语放在句尾，加以强调，是为it句型。 【例】 It is a pity that we won’t be able to go to the south to spend our summer vacation.我们不能去南方度过我们的暑假很遗憾。 为表示强调，常以形式主语it引导从句。It+谓语+引导词+从句。由于主语从句一般被认为是单数形式，形式主语代表真正的主语，因此要用it。因此形式主语的谓语动词、be动词+表语均为第三人称单数形式或过去式。 英国桂冠诗人约翰·梅斯菲尔德说：“快乐的日子使人睿智。”很多考生可能觉得这句话应该反过来说，但其实复习过一段时间以后，面对着越来越复杂的难题，你就会发现，保持快乐的心态，复习效率自然而然就会提高。