名词性从句讲义.doc

名词性从句讲义一. 名词性从句在句子中起名词性作用的从句叫做名词性从句(Noun Clauses). 名词性从句在句中的作用相当于名词或名词短语, 在复合句中担当主语, 宾语, 表语和同位语等. 因此根据它在句中不同的语法功能可分为: 主语从句, 宾语从句, 表语从句和同位语从句.引导名词性从句的连接词可分为三种:连接词: that, whether, if (不在从句中做任何成分)连接代词: what, who, whom, which, whose和wh+ever (通常在从句中做主语,宾语,表语等)连接副词: when, where, why, how以及wh/h+ever(通常在从句中做状语)二.主语从句 1.概念: 主语从句是在复合句中充当主语的从句.2.连接词: that只起连接主句和从句的作用,在从句中不担任任何成分,本身没有词义,不可省略whether 连接主句和从句, 在从句中不担任任何成分, 但本身有选择或是否的含义whether与if 区别（一）引导宾语从句，一般既可用whether也可用if。但1 or not放在whether之后时，只能用whether不用if。I dont know whether or not he will come. 我不知道他是不是回来。注1：如果or not放在whether所引导的从句句尾，则可以用if来替换。I dont know whether/if he will come or not.我不知道他是不是回来。2 在强调任意选择时,用whetheror,此时不用if替换whether。He asked me whether I wanted to go there by train or by bus.他问我是想乘火车还是坐公共汽车去那里。注：whether和or一起还有“不管”之意,引导让步状语从句。Whether he drives or takes the train, he will be here on time.不管开车来还是乘火车来，他都会准时到。3 虽引导宾语从句，但为了强调宾语部分，也可把从句放在句首，此时只用whether不用if。Whether he will come I am not sure.他是不是来我拿不准。4 从句作介词宾语时只用whether不用if。It depends on whether it will be fine.那得看是不是晴天。5 作discuss等动词的宾语时，用whether不用if。We discussed whether we should close the shop.我们讨论是不是该关掉商店。6 句子中有if引导的条件句，如再有表示“是否”的宾语从句，用whether不用if。He asked me whether Id move to New York if I got the job.他问我如果我得到那份工作是否会搬家到纽约。7 容易产生歧义时用whether不用if来表示“是否”。 Please let me know if you need help. 如果你需要帮助请告诉我。或：请告诉我你是否需要帮助。对比：Please let me know if you need help.请告诉我你是否需要帮助。8 如果宾语从句为否定句时，则只用if不用whether。I dont know if it wont rain tomorrow.我不知道明天是不是会下雨。（二）在引导主语从句、表语从句、同位语从句时一般用whether不用if。如：Whether it is true remains a question.(主语从句)那是不是真的还是个问题。The question is whether it is true.(表语从句)问题是是不是真的。We have a doubt whether it is true.(同位语从句) 我们怀疑那是不是真的。注:whether引导主语从句放在主句之后时可用if来代替。It is unclear whether/if he likes the present.他是不是喜欢那个礼物还不清楚。（三）用在动词不定式之前时用whether不用if。I dont know whether to go there at once. 我不知道是不是该立刻去那里。Wh-词包括who, whom, whose, whoever, what, whatever, which, whichever等连接代词和where, when, how, why等连接副词。连接主句和从句, 本身有词义,并在从句中充当句子成分.3.主语从句的语序：主语从句要求使用陈述句语序例如: That light travels in straight lines is known to all. Whether we will hold a party tomorrow depends on the weather.What he wants is a book. How he was successful is still a puzzle. 4. 常用的一些结构:1).用it 作形式主语的结构.：That-从句作主语通常用it作先行词，而将that-从句置于句末,例如： It is 名词从句 It is a fact /an honor /a pleasure/common knowledge/a pity that例如: It is a fact that the earth goes around the sun. It is a pity that you have missed the wonderful movie.it is 形容词从句 it is natural/strange/surprising/clear that 例如: It is strange that he knew nothing about it. It is surprising that he has passed the difficult exam. it is不及物动词从句 It seems/appears (to somebody) that 似乎 It happens (to somebody) that 碰巧It occurs (to somebody) that某人突然想到It seems that he has lost something.例如: It happened that I had read the book before.It seems/ appears that he has known the secret.itis+过去分词+从句 It is said/ reported/ believed/ proved/found thatit+及物动词+宾语+that从句It worried me a lot that his hair was turning gray.It shocked us that Peter went out without anyone knowing it.it doesnt matter + how/whether从句It doesnt matter whether he is right or not.It doesnt matter how we will get there.三.宾语从句1.概念: 在句子中起宾语作用的从句叫做宾语从句。宾语从句可以作及物动词的宾语，作短语动词的宾语，介词的宾语。2.连接词: 宾语从句的引导词和主语从句的引导词基本相同。但是if 一词可以用于宾语从句,用法同whether. 同时宾语从句中的that 一词可以省略例如: Everybodyknowsthat you cant get anything without working.DoyouknowwhereIcanfindher? Pleasegoandfindoutwhenthetrainwillarrive.Iaminterestedinwhatsheisdoing注意:1.否定的转移: 有些表示思想和感情的动词之后(如: 在suppose, believe, expect, think, feel等)的宾语从句中的否定式可以转移到这些动词之前。 例如:Idontsupposeyoureusedtothisdiet. Idontimagineshewillwinthechampionship. Ididntexpectshewouldpasstheentranceexamination. Idontthinkwehavegotenoughtime. Idontbelieveshellarrivebefore8. 2. 宾语从句在常见的动词wish /order, suggest, demand, insist, request, advise等后用虚拟结构四. 表语从句1. 概念: 表语从句置于连系动词(be)后面做表语。2.连接词: 主要有四类:1）由不充当任何句子成分的连词that, whether引起的表语从句。that在表语从句中不可以省掉。例如：What I mean is that we should help each other.The problem is whether we can finish the work on time.2) 由连词who, what, which 等引导的表语从句。这些词不但可以起连接作用，还可以在句中做主语、宾语和表语。例如：What concerns me most is who will be my teacher next term. China is not what she was yesterday.3）由连接副词when, where , why , how 引导表语从句,并在表语从句中做状语例如：This is when I really get to know Americans. The question under discussion is where we will hold the meeting. 4）由连词 because, as if, as though 引导的表语从句。例如：It looks as if it is going to rain tonight.That we made the mistake is because we are careless. 五. 同位语从