高中名词性从句知识点汇总

1、名词性从句名词性从句知识点汇总在句中起名词作用从句叫做名词性从句。名词性从句的功能相当于名词短语，在复合句中能担当主语、宾语、表语、同位语等。根据它在句中不同的语法功能，名词性从句分为主语从句、宾语从句、表语从句和同位语从 句。名词性从句的引导词可分为3类：从属连词：只起连接作用，不充当从句中的任何成分。包括：that,whether,if,as if,as though连接代词：既起连接作用，本身又作从句的主语、宾语、表语或定语。包括：who,whom,whose,which,what,whoever,whatever,whichever,whomever.连接副词：既起连接作用，本身又作从

2、句的状语。包括 :whe n, where,how,why s一、主语从句可以直接放在句首，也可以用形式主语 it代替，将主语从句放在句末。1. that引导的主语从句that引导主语从句时只起连接作用，没有实际意义，也不在从句中作任何成分，但不能省略。That the earth moves around the sun is known to all.2. whether,if引导主语从句whether :引导主语从句既可以放在句首，也可以放在句末，只起连接作用，不作成分if :引导主语从句只能放在句末，前面用it作形式主语。whether you can succeed or not d

3、epe nds on how hard you work at it. It is unknown whether/if he has agreed to my pla n.3. 连接代词或连接副词引导主语从句连接代词在从句中作主语、宾语、表语或定语。连接副词在从句中作状语。What they n eed are a car and some water.Why they sudde nly disappo in ted still rema ins a mystery.4.it作形式主语的主语从句1)代+be+adj./n./过去分词+that从句It has bee n predicted

4、 that mobile phones might soon replace our wallets.2) lt+seem(ed)/happen(ed)等不及物动词及短语+that从句 It seemed that each of them was satisfied with the results.3) It doesn 't matter+how/whetherIt does n ' t matter whether he will jo in the club or not.4) that引导主语从句出现在疑问句中，用 it作形式主语，把主语从句后置 Is it lik

5、ely that your friend will come this eve ning?5)当主语从句出现在感叹句中时，要以it作形式主语，而把主语从句后置What a pity it is that you missed a won derful football match!二、宾语从句1 .动词接宾语从句1)宾语从句紧跟在及物动词后：She won dered who had sent the flowers.2)常用 it 作形式宾语：He had made it clear that the meeting not be postponed.(有宾补的情况下)2 .介词接宾语从句1

6、)介词后面可以跟whether和wh-类连接词引导的宾语从句He only cares about whether the eyewit ness has give n true in format! on.2)介词except,but,besides,in后有时可以直接接that引导的宾语从句。除这些之外， that引导的从句一般不直接作介词的宾语。其他介词后接that从句作宾语时，必须用it作形式宾语。I didn ' t tell him anything except that I needed the money.You may depe nd on it that I sh

7、ould always help you.3 .系表结构接宾语从句Sure,certa in, glad,pleased,happy,afraid,surprised,satisfied,sorry 等表示情感的形容词与 be 其后 起构成系表结构, 的从句也可视为宾语从句。I 1 m con fide nt that you will get the job.I 1 m glad that you can come here on time.4 .只用whether不用if的情况1) 在介词后弓 I 导宾语从句：Everyth ing depe nd on whether you agree

8、 with us.2) 宾语从句置于句首：Whether they likethe presents, we don1 t know.3) 与 or not 连用时：I want to know whether or not the train goes to King street.4) 与不定式连用时:l can ' t decided whether to stay.5) 在动词 discuss, wonder, doubt, leave, put 后弓 | 导宾语从句：We discussed whether we should close the shop.5 .宾语从句中不

9、能省略that的情况1) 宾语从句前有插入语： We hope, on the con trary,that he will stay at home with us.2) 宾语从句紧跟在间接宾语之后时，或主语状语置于宾语从句之前时He told me that he was leaving for Australia.I realized at once that I hadn1 t turn off the gas.3) 当it作形式宾语，后接that引导的宾语从句时I don ' t think it polite that they left without saying th

10、anks to us.4) that引导的从句位于句首That our team will winj believe.5) 宾语从句在except,but,besides,in等介词之后He also likes play ing the pia no besides that he is good at play ing basketball.6) that引导的从句与其他引导词引导的从句作并列宾语I know where we will go and that we1 II be back in three days.7) 多个并列的that引导的宾语从句，只有第一个that可以省略8)

11、宾语从句的主语是非谓语动词或从句The doctor said that tak ing exercise was the best way of los ing weight.9) 宾语从句的主语是this,that或有this,that修饰时She told me that that was why she was late.10)宾语从句为主从复合句，从句位于宾语从句的前部I promised that if anyone came to set me free,! would make him king over the earth.三、表语从句表语从句位于主句的连系动词be,seem

12、,look,sound,taste,feel,remain,appear等之后。1. that,whether引导的表语从句只起连接作用，不作成分，that无词义，不能省略。Whether意为是否，不能换成上One problem is that I don ' t look any different from other people.2. as if,as though, because1)as if,as though引导的表语从句，可用陈述语气，也可用虚拟语气。常跟在特定动词后面， seem,appear,look,taste,sound,feel 等。You look as

13、 if you ' ve had a good time. He looks as if he were from the Mars.2) because引导表语从句时，主句的主语不能用 reasono如果主句的主语是reason,表语从句用that,不能 用 why 或 becauseo 常见句型为 The reason(why).is that.3) wh类连接词引导的表语从句，通常不含有意义，而是分别表示具体地点、时间、原因和方式等。 This is why I think my happiest days will be in the future.4)表语从句用虚拟语气的情况

14、：主句的主语是 advice, dema nd, order, suggesti on, requireme nt, request, comma nd等时，表语从句用虚拟语气，结构是(should)+动词原形。His suggesti on is that we (should) set off at once.四、同位语从句往往用来说明某些名词的实际内容或对该名词作进一步解释。这类名词常见的有：fact,n ews,idea,truth,hope,problem,i nformati on, wish,suggesti on,con clusi on 等。1. that引导同位语从句：通常

15、从句意义完整，that无词义，只起连接作用，不可省略。I ' ve got a feeling that one day he' II be famous.2. whether, when, where, why, how等引导同位语从句。 whether意为是否，在句子中不作成分，其他的连接 词具有实义，并在句中作成分。If不能引导同位语从句。The stude nt asked me the questi on whether the book was worth readi ng.I have no idea whe n we will have a long holid

16、ay.3. 被分隔的同位语从句：主句的谓语比较短时，同位语从句常被分隔，形成：主语+谓语+同位语从句The no tice came around two in the after noon that the meet ing would be postp on ed.4. 同位语从句中的虚拟语气：当主语是advice,proposal,suggestion等时，要用虚拟语气，(should)+动词原形。The suggesti on came from the chairma n that the rule (should) be adopted.5. 同位语从句和定语从句的区别1)修饰词：

17、同位语从句前被修饰词只能是idea, fact, news, hope等有一定内涵的名词。定语从句前被修饰词可以是名词、代词、主句的一部分或整个主句。2)性质：同位语从句相当于一个名词，对前面的抽象名词进行说明和解释 定语从句相当于一个形容词，对先行词进行修饰或限制。3)连接词：有些连接词how,whether,what可引导同位语从句，不能引导定语从句；而which能引导定语从句，去 J不能单独使用引导同位语从句。例如：The questi on whether we n eed it has not bee n con sidered.This is a simple idea,but o

18、ne which is hard to put into practice.4)成分：that在同位语从句中仅起连接作用，不充当任何成分，不能省略，也不能用which来代替。that引导定语从句，在从句中一般作主语或宾语，指物时可以用which来代替，作宾语常被省略。But they forget the fact that Can ad a is 5,500 km from coast to coast.The n ews that he told us just now is un believable.五、连接词what与that的区别1. 引导名词性从句时，what在从句中要充当句子成

19、分，意为“的事物/地方/人"；that不作任何成分，只起连接作用，没有实际意义。What the post says is in teresti ng.I heard that he joined the army.2. 当名词性从句已有疑问词引导时，不可再加thatI don 1 t understand what you said just now.六、wh -ever 与 no matter wh -的区另 Uwh既可以引导名词性从句，又可以引导让步状语从句；而n。matterwh-只能引导让步状语从句。He wouldn 1 t believe whatever I said

20、.Whatever I said,he wouldn 1 t believe me.七、连接词whether和if的区别在主语从句中用it作形式主 whethero1在引导主语从句、表语从句、同位语从句时，一般用whether不用if。 2.语时，whether和if者何以用，但在句首时只能用Whether they will have a picnic tomorrow isn1 t know.It isn ' t certain whether/if you' II attend the meeting.八、doubt,be sureI doubt whether/if.

21、doubt 用于肯定句，用 whether/ifThere ' s no doubt that. doubt 用于否定句，用 thatI ' m sure that. sure 用于肯定句，用 thatI 1 m not sure whether/if. sure 用于否定句，用 whether/if课堂练习一、在下列句子空白处填入适当的单词：1. Grandma pointed to the hospital and said," That 1 s I was born.2.1s it true that Mike refused an offer from Yal

22、e Uni versity yesterday?Yeah,but I have no idea he did it;that' s one of his favorite university.3. the delayed flight will take off depe nds much on the weather.4. From space,the earth looks blue.This is about seventy -one percent of its surface is covered by water.5. Do no t let any failure di

23、scourage youjor you can n ever tell close you may be to victory.6.1 made a promise to myself this year,my first year in high school,would be differe nt.7.Scie ntists study huma n brains work to make computers.8.1 1 m afraid he 1 s more of a talker than a doer,which is he never finishes anything.9. w

24、orries me a lot is that I keep forgett ing what I have just done.1.1 1 really don 1 t know it was that I put my wallet.二、单句改错1.50 if they said was true,! would have a cha nee of winning the prize.2. Word came that free souve nirs would be give n to anyone whoever come first.3. The reas on why he was late is because he was n1 t in formed of the cha nge of time.4. The n ews our team won the match was en couragi ng.4.1 can n ever un dersta nd how Mary said nothing about her wron gs.1.1 have bee n admitted to Beiji