在句子中起名词作用的句子叫名词性从句(Noun Clauses)。 名词性从句的功能相当于名词词组, 它在复合句中能担任主语、宾语、表语、同位语、介词宾语等，因此根据它在句中不同的语法功能，名词从句又可分别称为主语从句、宾语从句、表语从句和同位语从句。
1. It 作形式主语和it引导强调句的比较
a) It is a pity that you didn’t go to see the film. 你不去看那场电影真可惜。
b) It doesn’t interest me whether you succeed or not. 我对你成功与否不感兴趣。
c) It is in the morning that the murder took place. 谋杀案是在早上发生的。(强调句型)
d) It is John that broke the window. 是John打碎的窗户。(强调句型)
2. 用it 作形式主语的结构
(1) It is + 名词 + 从句
It is a fact that … 事实是…
It is an honor that …非常荣幸
It is common knowledge that …是常识
(2) It is + 形容词 + 从句
It is natural that… 很自然…
It is strange that… 奇怪的是…
(3) It is + 不及物动词 + 从句
It seems that… 似乎…
It happened that… 碰巧…
It appears that… 似乎…
(4) It + 过去分词 + 从句
It is reported that… 据报道…
It has been proved that… 已证实…
It is said that… 据说…
(2)It is said /reported…结构中的主语从句不可提前。例如：
正确表达：It is said that President Jiang will visit our school next week.
错误表达：That President Jiang will visit our school next week is said.
正确表达：It occurred to him that he failed in the examination.
错误表达：That he failed in the examination occurred to him.
(4)It doesn’t matter how/whether …结构中的主语从句不可提前。例如：
正确表达：It doesn’t matter whether he is wrong or not.
错误表达：Whether he is wrong or not doesn’t matter.
正确表达：Is it likely that it will rain in the evening?
错误表达：Is that will rain in the evening likely?
4. what 与that 在引导主语从句时的区别
what 引导主语从句时在句时在从句中充当句子成分，如主语.宾语.表语，而that 则不然。例如：
a) What you said yesterday is right.
b) That she is still alive is a consolation
宾语从句就是在复合句中作宾语的名词性从句，通常放在主句谓语动词 (及物动词) 或介词之后。
(1) 由that引导的宾语从句(that 通常可以省略), 例如：
I heard that be joined the army. 我听说他参军了。
(2) 由what, whether (if) 引导的宾语从句，例如：
a) She did not know what had happened. 她不知道发生了什么。
b) I wonder whether you can change this note for me. 我想知道你是否能帮我改一下笔记。
She told me that she would accept my invitation. 她对我说她会接受我的邀请。
Our success depends upon how well we can cooperate with one another. 我们的成功取决于我们之间的合作。
I am afraid (that) I’ve made a mistake. 我恐怕我已经犯了一个错误。
注意：that 引导的从句常跟在下列形容词后作宾语：anxious, aware, certain, confident, convinced, determined, glad, proud, surprised, worried, sorry, thankful, ashamed, disappointed, annoyed, pleased, hurt, satisfied, content 等。也可以将此类词后的that从句的看作原因状语从句。
4. it 可以作为形式宾语
it 不仅可以作为形式主语，还可以作为形式宾语而真正的宾语that 从句则放在句尾，特别是在带复合宾语的句子中。 例如：
We heard it that she would get married next month. 我听说她下个朋就会结婚了。
5. 后边不能直接跟that 从句的动词
这类动词有allow, refuse, let, like, cause, force, admire, condemn, celebrate, dislike, love, help, take, forgive等。这类词后可以用不定式或动名词作宾语，但不可以用that引导的宾语从句。如：
正确表达：I admire their winning the match.
错误表达：I admire that they won the match.
有些动词不可用于“动词+间接宾语+that从句“结构中，常见的有envy, order, accuse, refuse, impress, forgive, blame, denounce, advise, congratulate等。例如：
正确表达：He impressed the manager as an honest man.
错误表达：He impressed the manager that he was an honest man.
若主句谓语动词为think, consider, suppose, believe, expect, fancy, guess, imagine等，其后的宾语从句若含有否定意义，一般要把否定词转移到主句谓语上，从句谓语用肯定式。例如：
I don’t think this dress fits you well. 我认为这件衣服不适合你穿。
表语从句在复合句中作表语的名词性从句，放在系动词之后，一般结构是“主语+连系动词+表语从句”。可以接表语从句的连系动词有be, look, remain, seem等。引导表语从句的that常可省略。另外，常用的还有the reason is that… 和It is because 等结构。例如：
1) The question is whether we can make good preparation in such a short time.
2) This is why we can’t get the support of the people.
3) But the fact remains that we are behind the other classes.
4) The reason he is late for school is that he missed the early bus.
1) The king’s decision that the prisoner would be set free surprised all the people.
2) The order that all the soldiers should stay still is given by the general.
He got the news from Mary that the sports meeting was put off.
1) The news that he told me is that Tom would go abroad next year.(他告诉我的消息是汤姆明年将出国。)(第一个that引导的从句是定语从句，that在从句中作宾语)
2)The news that Tom would go abroad is told by him.(汤姆将出国的消息是他讲的。)(同位语从句，that在句中不作任何成分)
1.____he does has nothing to do with me.
A. whatever B. No matter what C. That D. If
2. The manager came over and asked the customer how____
A. did the quarrel came about B .the quarrel had come about
C. had the quarrel come about D. had the quarrel come about
3. Energy is ____makes thing work..
A. what B. something C. anything D. that
4. Information has been put forward ____ more middle school graduates will be admitted into universities.
A. while B. that C. when D. as
5. This is ___the Shenzhou V Spaceship landed.
A. there B. in which C. where D. when
6. They have no idea at all____.
A. where he has gone B. where did he go
C. which place has he gone D. where has he gone
7. The doctor did a lot to reduce the patient’s fear ____he would die of the disease.
A. that B. which C. of which D. of that
8. The order came ___the soldiers ____the small village the next morning.
A. that ;had to leave B. that; should leave
C. /; must leave D. when; should leave
9. ___is no possibility ____Bob can win the first prize in the match.
A. There; that B. It; that C. there; whether D. It; whether
10. The question came up at the meeting_____ we had enough money for our research.
A. that B. which C. whether D. if
11. Is _____he said really true?
A. that B. what C. why D. whether
12.____the meeting should last two days or three days doesn’t matter.
A. That B. Whether C. If D. Where
13. It worried her a bit _____her hair was turning gray.
A. while B. if C. that D. for
14. ???_____more countries can use natural energy in the future remains to be seen.
A. Whether B. This C. who D. If
15.____he will go to work in a mountain village surprises all of us.
A. What B. That C. Whether D. If
16. ____you don’t like him is none of my business.
A. What B. That C. Who D. How
17.____all the inventions have in common is ____they have succeeded.
A. What; what B. That; that C. what; that D. That ; what
18. ____appeared to me that he enjoyed the food very much.
A. What B. It C. All that D. That
19. It is widely ______that smoking can cause cancer.
A. believed B. think C. say D. hoped
20. ____caused the accident is still a complete mystery.
A. What B. That C. How D. Where
1—5 ABABC 6—10 AABAC 11—15 BBCAB 16—20 BCBAA