名词性从句讲义1

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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 don’t 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 don’t 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whether…or,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 I’d 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 don’t know if it won't 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：

⑴Whether it is true remains a question.(主语从句)那是不是真的还是个问题。

⑵The question is whether it is true.(表语从句)

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问题是是不是真的。

⑶We 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 don’t 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：

①It 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.

②it 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.

③it 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.

④it＋is+过去分词+从句

It is said/ reported/ believed/ proved/found that…

⑤it+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.

⑥it doesn’t matter + how/whether从句

It doesn’t matter whether he is right or not.

It doesn’t 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: Everybody knows that you can’t get anything without working.

Do you know where I can find her? Please go and find out when the train will arrive.

I am interested in what she is doing

注意: