知识点——-名词性从句(二)主语从句课件

知识点名词性从句（二）主语从句知识点 名词性从句（二）主语从句名词性从句（二）主语从句【知识点解析知识点解析】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 doesnt matter too much.名词性从句（二）主语从句【知识点解析】一、主语从句的连词分三名词性从句（二）主语从句【知识点解析知识点解析】（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。名词性从句（二）主语从句【知识点解析】（2）用连接代词引导名词性从句（二）主语从句【知识点解析知识点解析】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.）名词性从句（二）主语从句【知识点解析】whatever=名词性从句（二）主语从句【知识点解析知识点解析】（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 hasnt been made public.名词性从句（二）主语从句【知识点解析】（3）用连接副词whe名词性从句（二）主语从句【知识点解析知识点解析】二、it 作形式主语的主语从句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。这分四种情况：(1)对于以连词that引导的主语从句，通常用形式主语it替代主语从句：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 common knowledge that 是常识名词性从句（二）主语从句【知识点解析】二、it 作形式主语的名词性从句（二）主语从句【知识点解析知识点解析】类似的名词还有：a pity；a wonder；a good thing；no wonder；surprise等。It is a mystery to me how it all happened.It is common knowledge that the whale is not a fish.It is no surprise that Bob should have won the game.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 重要的是名词性从句（二）主语从句【知识点解析】类似的名词还有：a p名词性从句（二）主语从句【知识点解析知识点解析】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.It is doubtful whether she will be able to come.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.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。名词性从句（二）主语从句【知识点解析】类似的形容词还有：st名词性从句（二）主语从句【知识点解析知识点解析】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 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.名词性从句（二）主语从句【知识点解析】It is+名词性从句（二）主语从句【知识点解析知识点解析】It seems不及物动词（happened/appears/doesnt matter/makes no difference/occurred）that 主语从句不可提前 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.(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：Whether they would support us was a problem.他们是否会支持我们还是一个问题。It was a problem whether they would support us.他们是否会支持我们还是一个问题。名词性从句（二）主语从句【知识点解析】It se名词性从句（二）主语从句【知识点解析知识点解析】(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：What we need is money.我们需要的是钱。What I want to know is this.我想知道的就是这一点。有时也可将助用形式主语。如：It is clear enough what he meant.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：Is it true that he is the girls father?他是那女孩的父亲，是真的吗？How is it that you are late again?你怎么又迟到了？名词性从句（二）主语从句【知识点解析】(3)对关系代词型w名词性从句（二）主语从句【知识点解析知识点解析】三、连词that的省略问题 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：That you didnt go to the talk was a pity.很遗憾你没去听报告。(that不可省)It was a pity(that)you didnt go to the talk.很遗憾你没去听报告。(that可省)名词性从句（二）主语从句【知识点解析】三、连词that的省略名词性从句（二）主语从句【练习练习】1._ Barbara Jones offers to her fans is honesty and happiness.A.Which B.What C.That D.Whom【答案】B【解析】考查名词性从句中的宾语从句。由句中的is可知其前面是由what引导的主语从句，且what在从句中作offer的宾语，故答案为B项。名词性从句（二）主语从句【练习】1._ Ba名词性从句（二）主语从句【练习练习】2.The villagers have already known _ well do is to rebuild the bridge.A.this B.that C.what D.which【答案】C【解析】考察宾语从句和主语从句。村民们已经知道我们将要做的事情是重建这座桥，后面的宾语从句的主语从句中缺少主语且指物，所以选择what。名词性从句（二）主语从句【练习】2.The village名词性从句（二）主语从句【练习练习】3.It was never clear _ the man hadnt reported the accident sooner.A.that B.how C.when D.why【答案】D【解析】考查主语从句。句意：这名男子没有早点报告这次事故的原因根本没有搞清楚。It在句中是形式主语，真正的主语是why引导的主语从句。名词性从句（二）主语从句【练习】3.It was neve名词性从句（二）主语从句【练习练习】4._ some people regard as a drawback is seen as a plus by many others.A.Whether B.What C.That D.How【答案】B【解析】本题考查主语从句。句意：一些人眼中的缺点是别人眼中的优点。从句中缺宾语，只能用what来引导，C中的That引导主语从句不做成分。名词性从句（二）主语从句【练习】4._ som名词性从句（二）主语从句【练习练习】5._ matters most in learning English is enough practice.A.What B.Why C.Where D.Which【答案】A【解析】考查主语从句。本题考查主语从句，且从句中缺少主语，所以A项正确。名词性从句（二）主语从句【练习】5._ ma