主语从句汇总讲解朱.doc

高中主语从句一.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.定义：1.主语：在简单句中，句子所要说明的主体或主题。Beijing is the capital of China. (名词是主语)To see is to believe. (不定式是主语)Reading every day is a good method to learn English well. (动名词短语是主语)2.主语从句：在句子中充当主语的句子叫主语从句。That she survived the accident is a miracle. （画下划线的句子为主语从句）三.连接词：连接主语从句和其他的成分的词或词组。1.从属连词that whether 无成分作用（1）that无含义，在句中不做成分，一般不可以省略。例如：That you will win the medal seems unlikely. （2）whether有含义(是否)，在句中不做成分，一般不可以省略。例如：Whether we will hold a party in the open air tomorrow depends on the weather. 2.连接代词 主语或宾语作用如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在主从中作need的宾语）Whatever we do is to serve the people.注：wh-（疑问词）+ever与no matter wh-的区别wh-+ever与no matter wh-都可以引导状语从句，但只有wh-+ever可以引导名词性从句，如主语从句。如：Whoever breaks the law should be punished. （主语从句） 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）连接副词： 状语作用如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 pubic.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,但也有例外四.it 在下面情况下经常用 it作形式主语，真正的主语从句放在句尾。 It is +名词+从句3It 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 是常识类似的名词还有：a pity；a wonder；a good thing； no wonder； surprise等。例如：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 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。 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. It is said that he was killed in the earthquake. It seems （happened / appears / doesnt matter / makes no difference / occurred ）that 如：It seems that they will win the game. It makes no difference whether he will attend the meeting or not. 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)例句4,5,6,1难点： It 作形式主语和it引导强调句的比较 It 作形