高中名词性从句讲解

名词性从句一定义：在句子中起名词作用的句子叫名词性从句 (Noun Clauses）。 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、介词宾语等，因此根据它在句中不同的语法功能，名词性从句又可分别称为主语从句、宾语从句、表语从句和同位语从句。1. His words are true.What he said is true.2. The dog sensed something delicious.The dog sensed that there was something delicious nearby.3. These are his words.These are what he said.4. My Chinese teacher, Mr Wang, is a kind person.The news that the plane had crashed made us sad.二引导名词性从句的连接词连词：在从句中不充当成分，只起连接作用that, 无实义whether, if 是否as if as though 似乎，好像连接代词：有词义，在句中担任主语，表语，定语或宾语。what, 什么who, 谁whom, 谁，作宾语whose, 谁的which, 哪一个whatever, whoever也可以引导。连接副词：有词义，在句中担任状语。when ,什么时候where, 什么地方why, 为什么how ,怎么样how many, how much, how often三主语从句1. 作句子主语的从句叫主语从句。Whether he will come or not is not known. 他来不来还不清楚。What he wants to tell us is not clear. 他要跟我们说什么，还不清楚。Who will win the match is still unknown. 谁能赢得这场比赛还不得而知。It is known to us how he became a writer. 我们都知道他是如何成为一名作家的。Where the English evening will be held has not yet been announced. 英语晚会将在哪里举行，还没有宣布。That he is late for school makes the teacher very angry. 他上学迟到让老师很生气。2. 有时为避免句子头重脚轻，常用形式主语it代替主语从句作形式主语放于句首，而把主语从句置于句末。主语从句后的谓语动词一般用单数形式。常用句型如下：（1） It + be + 名词 + that从句Eg. It is a pity that we wont be able to go to the south to spend our summer vacation.It is still a mystery what caused the accident.（2）It + be + 形容词 + that从句Eg. It is certain that he will win the match.It is true that he has made a very important discovery in chemistry.It is very likely that they will hold a meeting.It is strange that he should do that.It is important that we all should attend the meeting.It is strange that the man should have stuck to his silly ideas.（3）It + be + 动词的过去分词 + that从句Eg. It is said that he has gone to shanghai.(=He is said to have gone to shanghai) It is known to all that the gun powder was first invented by the Chinese. It is suggested that the work （should） be done with great care.（4）It + 不及物动词 + that 从句Eg. It seems that he has seen the film.(=He seems to have seen the film)It happened that the two cheats were there. (=The two cheats happened to be there) It occurred to me that I had forgotten to lock my door. It suddenly hit me that I had forgotten to lock my door. It struck me that I had forgotten to lock my door. It turned out that nobody remembered the address.注意：在主语从句中用来表示惊奇、不相信、惋惜、理应如此等语气时，谓语动词要用虚拟语气“(should) +do”，常用的句型有：It is necessary (important, natural, strange, etc.) that It is suggested (requested, proposed, desired, etc.) that3. 主语从句的时态：不受主句的时态影响和限制。（1）That he finished writing the composition in such a short time surprised us all.（2）Whether we will go for an outing tomorrow remains unknown.（3）Who will be our monitor hasnt been decided yet.（4） Whom we must study for is a question of great importance.（5）What caused the accident remains unknown.（6）Whatever you did is right.（7）Who the watch belongs to was lost is unknown.4.that 与 what 引导主语从句的区别what 有词义，在句中担任主语，表语，定语或宾语。that 无词义，不作任何成分，只起连接作用Eg. What has made him mad is not known yet. That she is still alive is a consolation.四宾语从句1. 定义：名词句用作宾语的从句叫宾语从句。2. 由连接词that引导宾语从句时，that在句中不担任任何成分，在口语或非正式的文体中常被省去，但如从句是并列句时,第二个分句前的that不可省。例如：He has told me that he will go to Shanghai tomorrow. 他已经告诉我他明天要去上海。We must never think (that) we are good in everything while others are good in nothing. 我们决不能认为自己什么都好，别人什么都不好。We all think (that ) she is working hard and that she will surely go to a very good university. 我们都认为她学习非常努力，一定能进一个非常好的大学。3. 在demand、order、suggest、decide、insist, desire, request, command等表示要求、命令、建议、决定等意义的动词后，宾语从句常用“（should）+ 动词原形”。例如：I insist that she (should) do her work alone. 我坚持要她自己工作。The commander ordered that troops (should) set off at once. 司令员命令部队马上出发。4. 可运用形式宾语it代替的宾语从句动词find, feel, consider, make, believe等后面有宾语补足语的时候,则需要用it做形式宾语而将that宾语从句后置.I think it necessary that we take plenty of hot water every day .我认为每天多喝开水是有必要的.I feel it a pity that I havent been to the get-together.我没去聚会,感觉非常遗憾.I have made it a rule that I keep diaries. 我每天写日记成了习惯.We all find it important that we (should) make a quick decision about this mater. 我们都认为对这件事马上做出决定很重要. 有些动词带宾语从句时需要在宾语与从句前加it这类动词主要有:hate, take , owe, have, see to.Eg. I hate it when they talk with their mouths full of food.我讨厌他们满嘴食物时说话.He will have it that our plan is really practical.他会认为我们的计划确实可行.We take it that you will agree with us.我们认为你会同意我们的. He took it for granted that his girlfriend would come back again.他想当然的认为女朋友会再回来。When you start the engine, you must see to it that car is in neutral. 开启发动机时, 一定要使汽车的离合器处于空挡位置.若宾语从句是wh-类,则不可用it代替 We all consider what you said to be unbelievable.我们都认为你所说的是不可信的.We discovered what we had learned to be valuable.我们发现我们所学到的东西都是有用的.5. 用who，whom, which, whose, what, when, where, why, how, whoever, whatever, whichever等关联词引导的宾语从句相当于特殊疑问句，应注意句子语序要用陈述语序。例如：I want to know what he has told you. 我想知道他告诉了你什么。 She always thinks of how she can work well. 她总是在想怎样能把工作做好。She will give whoever needs help a warm support. 凡需要帮助的人，她都会给予热情的支持。6. 用whether或if引导的宾语从句，其主语和谓语的顺序也不能颠倒，仍保持陈述句语序。此外，whether与if 在作“是否”的意思讲时在下列情况下一般只能用whether，不用if：a. 引导主语从句并在句首时；b. 引导表语从句时；c . 引导从句作介词宾语时；d. 从句后有“or not”时；e. 后接动词不定式时。Eg. Whether there is life on the moon is an interesting question. 月球上有没有生命是个有趣的问题。 The question is whether she should have a low opinion of the test?现在的问题是她是否应该有一个低意见的测试？ Everything depends on whether we have enough money. 一切要看我们是否有足够的钱。 I wonder whether he will come or not. 我想知道他来还是不来。 Can you tell me whether to go or to stay? 你能否告诉我是去还是留？7. 注意宾语从句中的时态呼应，当主句动词是现在时，从句根据自身的句子情况，而使用不同时态。例如：He studies English every day. （从句用一般现在时）He studied English last term. （从句用一般过去时）I know (that) he will study English next year. （从句用一般将来时）He has studied English since 1998. （从句用现在完成时）当主句动词是过去时态（could, would除外），从句则要用相应的过去时态，如一般过去时，过去进行时，过去将来时等；当从句表示的是客观真理，科学原理，自然现象，则从句仍用现在时态。例如：He says he studies English every day.The teacher told us that Tom had left for America 8. think, believe, imagine, suppose等等动词引起的否定性宾语从句中，要把上述主句中的动词变为否定式。即将从句中的否定形式移到主句中。例如：We dont think you are here. 我们认为你不在这。I dont believe he will do so. 我相信他不会这样做。9. 感叹句在宾语从句中的运用You cant imagine _ when they received these nice Christmas presents. A. how they were excited B. how excited they were C. how excited were they D. they were how excited 五表语从句1. 定义：在句中作表语的从句叫表语从句。引导表语从句的关联词与引导主语从句的关联词大致一样，表语从句位于连系动词后，有时用as if引导。其基本结构为：主语 + 系动词 + that从句。例如：The fact is that we have lost the game. 事实是我们已经输了这场比赛。Thats just what I want. 这正是我想要的。This is where our problem lies. 这就是我们的问题所在。That is why he didnt come to the meeting. 那就是他为什么不到会的原因。It looks as if it is going to rain. 看上去天要下雨了。2. that 注意：当主语是reason时，表语从句要用that引导而不是because。例如：The reason why he was late was that he missed the train by one minute this morning .3. what, who, which, whom, whose 除了在句中起连接作用外，还可以在从句中充当主语，宾语，表语，定语，并且各有各的词义。Eg. He has become what he wanted to be ten years ago. 他已经成为了他10年前想成为的。 The problem is who will travel with me to Beijing tomorrow.问题是谁与我明天前往北京。4. when ,where, why, how 在句中充当时间，地点，原因，方式状语。Eg. The question is when he can arrive at the hotel. 问题是，他什么时候可以到达酒店。 She has remained where I stood yesterday for an hour.她一直在我昨天站的地方站了一个小时。 That is why he was late. 那是他迟到的原因。5. as if as though, because等引导的表语从句。because 引导表语从句通常只用于“that this it is was because”结构中。as if as though 引导表语从句常置于系动词 look, seem, sound, be, become 等后面，用虚拟语气。Eg. The elephant feels as if though it were a wall. I was late for school this morning. Thats because I stayed up late last night. 我今天上学迟到了，因为我昨晚熬夜太晚了。6. 表示命令，建议的名词接表语从句，用虚拟语气，（should）+ 动词原形Eg. His suggestion is that we (should) climb all the way to the top of the hill.六同位语从句1. 定义：同位语从句说明其前面的名词的具体内容。同位语从句通常由that引导，可用于同位语从句的名词有advice、demand、doubt、fact、hope、idea、information、message、news、order、problem、promise、question、r