主语从句和主语从句的it.ppt

The Subject Clause,Grammar,Make sentences,Its certain that we will be late.,That well be late is certain.,We dont know whether he is coming or not,Whether he is coming is not known.,We dont know what he wants to tell us.,What he wants to tell us is not known.,When you will come back doesnt matter.,It doesnt matter when you will come back.,主语从句（Noun Clauses as the Subject）,连接词有： 连词that, whether； 连接代词who, what和which； 连接副词when, where, how和why。,连接词：,that 引导主语从句只起引导作用，本身无实际意义，在主语从句中不充当任何成分，但不能省略。,That she left him cut him to the heart. That he will come is certain.,1）从属连词：that， whether等.,由whether及其他连词引导的主语从句放在句首，句后都可。,Whether it will please them is not easy to say.,2)连接代词who ，what ，which, whatever, whichever, whoever,What seems easy to some people seems difficult to others. Which side will win is not clear.,3)连接副词when，where， how， why等。,Why he did it remains a mystery. When they will start is not known yet. How he became a great scientist is known to us all.,主语从句可以前置，也可以后置。用it做形式主语，而把主语从句，在句末，常用下面几种句型。,1. It + be + 表语 +主语从句 表语：（名词， 形容词，过去分词）,位置,It is said that Mr. Green has arrived in Beijing. It is reported that China has sent another manmade earth satellite into orbit.,2. It+不及物动词+主语从句 It seemed (happened, doesnt matter, has turned out) that,It happens that they were absent. It seems that Alice is not coming to the party at all.,It doesnt matter whether she will come or not.,3. It +及物动词（被动语态）+主语从句,It has been decided that the exhibition will not open on Sundays.,注意:,1）主语从句在句首时，必须由连接词引导，不能省略这些连接词；但是如果用it做形式主语，而把主语从句放在句末时，从属连词that可以省略。,误：They should like each other is natural. 正：That they should like each other is natural. 正：It is natural that they should like each other.,2)如果主语从句放在句首，不能用if引导，但是如果用it 做形式主语，而把主语从句放在句末时，也可以用if引导.,误：If Mary really heard him is really doubtful. 正：It was doubtful if Mary really heard him.,4 . 用于It is important / natural / necessary / impossible that.句型中, 主语从句应使用虚拟语气, 谓语动词用“should + 动词原形”的形式, should有时可以省略。,5. 在It + be+suggested/advised/ordered/requested/ insisted/required 中, that从句的谓语也应该用“should + 动词原形”的形式, should有时可以省略。,(1)主语从句中用陈述语序 What she is afraid of is their taking her to Paris. ( What is she afraid of Wrong ) (2)主语从句后谓语动词用第三人称单数 That they havent phoned is strange. (3)that引导的主语从句中，that不可被省略 That price will go up is certain.,主语从句需注意的问题,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。例如： It is a pity that you didnt go to see the film. It doesnt interest me whether you succeed or not. It is in the morning that the murder took place. It is John that broke the window.,what 引导主语从句时在句时在从句中充当句子成分，如主语宾语表语，而that 则不然。例如： 1) What you said yesterday is right. 2) That she is still alive is a consolation.,What在此引导主语从句,又做said的宾语,That 只起连接作用,不做成分,what 与that 在引导主语从句时的区别,Describe your mother with your partner.,Suggested structures: What my mot