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英语:什么是名词性从句?

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英语:什么是名词性从句?
英语:什么是名词性从句?
名词性从句
名词性从句:其功能相当于名词,根据其在句中充当的成分可分为主语,宾语,表语和同位语从句.名词性从句必须用陈述语序.
常见引导词:
1. that 无意义,在名词性从句中不充当成分;
2. whether/if “是否” , 在从句中不充当成分;
3. who “谁”,在从句中作主语, 口语中可作宾语, 表语;
4. whom “谁”,在从句中作宾语, 表语;
5. whose “谁的”,在从句中作定语,表语;
6. what “什么”,“…的”,在从句中作主语,宾语, 表语, 定语,含义没有明确的范围;
7. which “哪个,哪些”,在从句中作主语,宾语, 表语, 定语,含义有明确的范围;
8. when “何时”,在从句中作时间状语,表语;
9. where“何地”,在从句中作地点状语,表语;
10. why “为什么”,在从句中作原因状语,表语;
11. how “怎样,怎么”在从句中作方式状语,表语. 由how组成的短语也可引导名词性从句, 在从句中作状语,如how many, how long , how soon, how often, how far…
12. because “因为”,在从句中作原因状语;
13. as if/as though “好像,似乎”,在从句中不充当成分;
14. whoever “无论谁”,在主句和从句中都可作主语,宾语,表语;
15. whomever “无论谁”,在主句和从句中都可作宾语,表语;
16. whatever “无论什么”,在主句和从句中都可作主语,宾语,表语,定语;
17. whichever “无论哪个”,在主句和从句中都可作主语,宾语,表语,定语,含义有明确的范围;
一、主语从句
用作主语的从句.
常见引导词:that, whether, who, whom, whose, what, which, when, where, why, how, how much, how many, how long, how far, how soon, how often, whoever, whomever, whatever, whichever;
1. ________ the teacher said today was quite right.
2. _______ they are badly in need of help is quite clear.
3. ________ they will sell the house is not yet decided.
4. _________ was said here must be kept secret.
5. _________ makes mistakes must correct them.
6. It is a pity ______ she has made such a mistake.
7. ______ we will start is not decided yet.
8. ______ surprised me most was his manner.
9. ______ he was chosen monitor is clear.
10. _______ he has gone is still unknown.

注: 1、主语从句做主语,谓语用单数;但两个以上的从句做主语,谓语用复数;
What he says and what he does disagree.
2、可用“it”做形式主语,把主语从句放在后面;
主要有下列句型:
1) It +v.+ adj. / n. +从句
It is a shame that we missed the last train.
It is important that we should learn a foreign language.
It’s a pleasure that we’re going to have a party.
注:It is important /necessary/ natural/ a pity/strange/ impossible that sb. / sth. (should) do…
It is necessary that you not sleep in class.
2) It +不及物动词+从句
It seems/appears that he is from the USA.
It happened that his parents were out when he called.
3) It + be +过去分词+从句
It is said that... 据说……
 It is known to all that... 众所周知……
 It is reported that... 据报道……
 It is believed that... 据信……;人们相信……
 It is suggested that... 有人建议……
It is hoped that… 人们希望… …
It must be pointed out that... 必须指出……
It has been proved that... 已证明…….
It is said that Tom once studied in the USA.
It is reported that a storm is on the way.
It has been proved that the theory is correct.
3、在主语从句中,“that”放在句首时不能省略,若“it”做形式主语,“that”从句放在后面在口语中,可以省略“that”;
二、宾语从句
放在某个动词,介词或形容词后做宾语.
常见引导词:that, whether, if, who, whom, whose, what, which, when, where, why, how, how much, how many, how long, how far, how soon, how often, whoever, whomever, whatever, whichever;
1. I think ________ a healthy diet should contain a lot of green vegetables and fruit.
2. I wonder ________ you can do me a favor.
3. It depends on _________ the manager will agree to the plan or not.
4. The teacher asked little Tom _______ first discovered America.
5. He asked me ________ pronunciation was the best in our class.
6. He told me ________ had happened on his way to school. 
7. Do you think _______ team will win the match?
8. You can do ____________ you like.
9. I’ll give the job to ___________ has much work experience.
10. I don’t know __________ he will leave for America.
注:1. 含宾补时,常用下面句型:
主语+动词+it+宾补+宾语从句;
I find it necessary that we should ask him for advice.
2. 介词后常接wh-词引导的从句,很少接that引导的(介词but, except, in 除外), 若介词后的从句由 that引导,则须用it作形式宾语
After what seemed a long time, he returned home.
You may depend on it that they will support you.
She was fortunate in that she had friends to help her.
3. 在“be+adj.”后,常可接that引导的宾语从句,也可把其称为原因状语从句.
I’m afraid that I can’t accept your invitation.
She’s happy that her daughter had passed the exams.
4. 否定转移:“think, believe, suppose, guess, expect, imagine”等词所接的宾语从句若为否定式,常把否定词提前到在主句中.
He doesn’t believe we have finished our work.
I don’t think he cares about it, does he?
5. “that”引导的宾语从句做某动词或形容词宾语时,“that”可省略,但若有两个并列的“that”从句,后一个“that”不可省略;
I hear Tom is good at soccer and that he joined the club last week.
6. 宾语从句的时态特点
①主句若用现在时(含一般现在时,一般将来时,现在完成时),从句根据情况可用任何相应时态;
I hear they will be back in a week.
Do you know why he left without a word?
I’m not sure whether he has been to the Great Wall before.
②主句用过去式时,从句要用相应的过去时态(包括一般过去时,过去进行时,过去将来时,过去完成时);
She hesitated whether she would take our advice.
He told me his son was watching TV.
He said that he had been in London for two days.
注:当从句表示“真理,格言,谚语,科学事实”时,从句用现在时态;
My grandpa told me that the earth is round.
三、表语从句
表语从句放在系动词后,如be, seem, look等,用来说明,解释主语,使其具体化;
常见引导词:that, whether, who, whom, whose, what, which, when, where, why, how, how much, how many, how long, whoever, how far, how soon, how often, whomever, whatever, whichever, because, as if/as though;
1. What she wants to know is _______ computer she should buy.
2. The problem was ______ could do the work.
3. What I want to know is _________ answers are right.
4. He is late for school today; it is ________ he missed the first bus.
5. It seems _________ he is from the USA.
6. The trouble is _______ he has no work experience.
7. The question is ________ we should ask them for help.
8. He missed the first bus today; that is ________ he was late for school.
9. This is ________ you made the mistakes.
10. The problem is _______ he can get food and clothing.

注:1. 引导词通常不省略;
2. 当“reason”做主语时,表语从句用 “that”引导;
The reason for his illness is that he was caught in a heavy rain.
3. The truth/fact is that…
The trouble/difficulty/problem is that…
The fact is that he has never been there before.
The trouble is that we are short of money and technology.
四、同位语从句
同位语从句放在某名词后,对其进一步解释,说明该名词的具体内容.
常见引导词:that, when, where, whether, why, who, whom, whose, how…
同位语从句常放在下列名词后: news, word, idea, fact, truth, reason, thought, doubt, belief, hope, promise, possibility, order, proposal, advice, suggestion, demand…
There was little hope that they would survive.
Word came that our team had won.
I have no idea why she left.
They had the question whether he could pass the final exam.
He didn’t take my advice that we should set off earlier.