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）Δ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 hasn’t 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Δ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1It 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。