名词从句用法详解
 
一、概说
名词性从句,即指性质相当于名词的从句,它包括主语从句、宾语从句、表语从句和同位语从句。从高考的考查的实际情况来看,名词性从句考得最多的是宾语从句,其次是主语从句,再次是表语从句,而同位语从句则很少考查。
二、名词性从句的一般引导
1. 连接 that 只起连接作用,没有任何意思,也不充当句子成分,在宾语从句中可省略,但引导其他名词性从句时通常不省略。如:
I hope (that) you enjoy your holiday. 希望你假期过得好。
That he likes you is very obvious. 很显然他喜欢你。
2. 连接词 whether 也不充当句子成分,但有自己的意思,表示是否;引导宾语从句时,可换成 if,但引导其他名词性从句时不能换成 if。如:
He asked whether [if] I would show him the way. 他问我是否可以给他带路。
Whether it will do us harm remains to be seen. 是否对我们有害还要看一看。(引导主语从句,不能用 if 代替 whether)
3. 连接代词 who(m), whose, which, what 等,均有各自的意义,在从句中作主语、宾语、定语等。如:
That’s why she wanted to leave. 这就是她想离开的原因。
When we arrive doesn't matter. 什么时候到没有关系。
Tell me which one you like best. 告诉我你最喜欢哪一个。
4. 连接副词 when, where, why, how 等,也各自有自己的意义,在从句中作状语。如:
The question is how we should carry out the plan. 问题是怎样执行这个计划。
When she’ll be back depends much on the weather. 她什么时候回来在很大程度上要看天气。
Why he did it will remain a puzzle forever. 他为什么这样做将永远是一个谜。
三、名词性从句的重要引导词
1. what 用于引导名词性从句是一个十分重要的引导词,它可引导主语从句、宾语从句和表语从句,但不用于引导同位语从句。它引导的名词性从句有两个意思是:一是表示什么,带有疑问意味;二是表示“…,相当于:先行词+关系代词。如:
I don’t know what you want. 我不知道你想要什么。
I don’t know what you want is this. 我不知道你所想要的是这个。
2. what 引导名词性从句时可用作限定词,其后修饰名词。如:
I gave him what books I had. 我把我所有的书都给他了。
He gave me what money he had about him. 他把身边带有的钱全给了我。
注:what 后的名词可以是复数名词或不可数名词,但通常不能是单数可数名词,并且后接不可数名词时,有时可有little修饰,两者的区别是:what+不可数名词=所有的都,what little+不可数名词=虽少但全部。如:
What friends she has are out of the country. 她有的那些朋友全在国外。
We gave him what (little) help we could. 我们给了他我们力所能及的帮助。
3. whoever, whatever, whichever 等也可引导名词性从句,其意分别为的一切事或东西任何的人““…的任可人或物等。如
Whoever wants the book may have it. 任何人要这书都可拿去。
whether是什么意思
I’ll do whatever I can to help him. 我们将尽我们所能来挽救他。
Buy whichever is cheapest. 买最便宜的。
注意以下受汉语意思影响而弄错的句子:
任何人来都欢迎
误:Who comes will be welcome. / Anyone comes will be welcome.
正:Whoever comes will be welcome. / Anyone who comes will be welcome.
另外,它们也可引导让步状语从句,其意为无论…”不管…”,其意相当于 no matter who [what, which]。如:
Whatever happens, you must be calm. 不管发生什么情况,你都必须镇静。(whatever = no matter what)
He won't eat you, whoever he is. 不管他是谁,他也不能把你吃掉。(whoever = no matter who)
注:whoever 既用作主格也用作宾语;作宾语时不宜用 whomever,因为在现代英语中 whomever 这个已几乎废弃不用。
4. why  because 的用法区别。两者均可引导表语从句,但前者强调结果,后者强调的原因。如:
I had a cold. That’s why I didn't come. 我感冒了,因此我没来。
I didn’t come. That’s because I had a cold. 我没有来,那是因为我感冒了。
五、名词性从句的语序
名词性从句的词序与陈述句语序相同,尤其注意那些由连接代词who(m), whose, which, what 和连接副词 when, where, why 等引导的名词性从句,不要受它们在特殊疑问句中用法的影响而误用疑问句词序。如:
Why was she crying? 她为什么在哭?
I don’t know why he was crying. 我不知道她为什么哭。
六、名词性从句的时态问题
1. 当主句的谓语动词是过去式时,宾语从句若不是一个客观事实或真理,其谓语动词也必须用某种过去时态。如:
She said that she didn't want to know. 她说她不想知道。
I asked her whether she would agree. 我问她是否会同意
2. when, if 这两个词既可引导名词性从句,也可引导状语从句。当它们引导名词性从句且表示将来意义时,要直接使用将来时态;但当它们引导状语从句且表示将来意义时,则必须用一般现在时表示将来意义。如:
I don’t know when he will come, but when he comes, I’ll call you. 我不知道他什么时候,但当他来的时候,我会打电话给你。
句中第一个when 引导的是宾语从句,故用将来时态表示将来意义;第二个when 引导的是时间状语从句,故用一般现在时表示将来意义。
主语从句用法详解(例句丰富)
 
一、主语从句的引导词
主语从句通常由连词thatwhether、连接代词或连接副词以及关系代词型what引导。
1. that引导
That he is still alive is a wonder. 他还活着,真是奇迹。
That we shall be late is certain. 我们要晚了,这是确定无疑的。
That he should have ignored the working class was natural. 他忽视工人阶级是很自然的。
That she is still alive is a consolation. 她还活着是使人感到宽慰的。
That she became an artist may have been due to her father’s influence. 她成为画家可能是受她父亲的影响。
That you are coming to London is the best news I have heard this long time. 你将来伦敦是好久以来我听到的最好消息。
That she was chosen made a tremendous stir in her village. 她被挑选上,在她村                    子里引起很大轰动。
2. whether引导
Whether it will do us harm remains to be seen. 是否对我们有害还要看一看。
Whether they would support us was a problem. 他们是否会支持我们还是一个问题。
3. 连接代词引导
Whoever is top from wins the game when two matched players meet. 两强相争勇者胜。
Whichever (of you) comes in first will receive a prize. 无论(你们)谁先到都可以得奖。
Whichever you want is yours. 你要哪个哪个就是你的。
4. 连接副词引导
When we arrive doesn’t matter. 什么时候到没有关系。
How it was done was a mystery. 这是怎样做的是一个谜。
How this happended is not clear to anyone. 这件事怎样发生的,谁也不清楚。
How many people we are to invite is still a question. 邀请多少人还是一个问题。
Where I spend my summer is no business of yours. 我在哪里过暑假不关你的事。
5. 关系代词型what引导