名詞性從句相當于名詞，可分別作主句的主語、表語、賓語和同位語。因此，名詞性從句廳分為主語從句、表語從句、賓語從句和同位從句。
（一）引導名詞性從句的連接詞
1、連接代詞：who, whose, whom, what, which。有詞義，在從句中擔任成分，如主語、表語、賓語、或定語等。
2、連接副詞：when, where, why, how。有詞義，在從句中擔任成分，作狀語。
3、連接詞：that, whether, if, as if。that 無詞義，在從句中不擔任成分，有時可省略；if (whether), as if雖有詞義，但在從句中不擔任成分。
注意：連接代詞與連接副詞在句中不再是疑問句，因而從句中謂語不用疑問式。連接代詞與連接副詞在從句充當句子成分，連接詞whether 和if（是否），as if（好象）在從句中不充當句子成分，只起連接作用。根據句義，如果連接代詞與連接副詞，whether、if 和as if都用不上時，才用that作連接詞（that本身無任何含義）。
（二）主語從句
1、主語從句在復合句作主語。
e.g. Who will go is not important.
2、用it作形式主語，主語從句放在句末。
e.g. It doesn’t matter so much whether you will come or not.
3、that引導主語從句時，不能省略。
e.g. That he suddenly fell ill last week made us surprised.
（三）表語從句
1、表語從句在復合句中作表語，位于系動詞之后。
e.g. The question was who could go there.
2、引導表語從句的連接詞that有時可省去。
e.g. My idea is (that) we can get more comrades to help in the work.
（四）賓語從句
1、賓語從句在復合句中作賓語。引導賓語從句的連詞that一般可省略。
e.g. I hope (that) everything is all right.
2、介詞之后的賓語從句，不可用which或if連接，要分別用what或 whether。
e.g. I’m interested in whether you’ve finished the work..
I’m interested in what you’ve said.
3、whether與if都可以引導賓語從句，常可互換。但下面情況不能互換。
①賓語從句是否定句時，只用if，不用whether。
e.g. I wonder if it doesn’t rain.
②用if 會引起誤解，就要用whether。
e.g. Please let me know whether you want to go.（此句如果把whether改成if，容易當成條件句理解）
③賓語從句中的whether 與or not直接連用，就不能換成if；不直接連用，可換。
e.g. I don’t know whether or not the report is true.
I don’t know whether/ if the report is true or not.
④介詞后的賓語從句要用whether引導。whether 可與不定式連用。whether也可引導主語從句、表語從句、同位語從句，還可引導讓步狀語從句，以上均不能換成if。但引導條件從句時，只能用if，而不能用whether。
e.g. It depends on whether we have enough time.
They don’t know whether to go there.
Please come to see me if you have time.
（五）同位語從句
同位語從句在句中作某一名詞的同位語，一般位于該名詞（如：news, fact, idea, suggestion, promise等）之后，說明該名詞的具體內容。
e.g. I have no idea when he will be back.
The fact that he had not said anything surprised everybody.
練習：名詞性從句
一、判斷下列各句哪句含有名詞性從句，并指出是什么從句：
1. China is no longer what it used to be.
2. The truth that the earth turn around the sun is known to all.
3. It was snowing when he arrived at the station.
4. How he persuaded the manager to change the plan is interesting to us all.
5. The news that they had won the game soon spread over the whole school.
6. The news that you told me yesterday was really disappointing.
7. That is where Lu Xun used to live.
8. He spoke as if he understood what he was talking about.
9. Do you remember the teacher who taught us English at middle school?
10. I wonder why she refused my invitation.
二、用適當的連詞填空：
1. I can’t decide ____________ dictionary I should buy.
2. That’s ____________ he refused my invitation.
3. I am very interested in ____________ he has improved his pronunciation in such a short time.
4. ____________ we need is more time.
5. The fact ____________ she had not said anything at the meeting surprised everybody.
6. ____________ and ____________ they will meet has not been decided yet.
7. Please tell me ____________ you are waiting for.
8. Is that ____________ you are looking for?
9. Would you please tell me ____________ the nearest post office is?
10. I don’t know ____________ he will agree to the plan or not.
三、選擇填空：
1. Do you see _____ I mean?
A. that B./ C. how D. what
2. Tell me_____ is on your mind.
A. that B. what C. which D. why
3. We must stick to _____ we have agreed on.
A. what B. that C. / D. how
4. Let me see _____.
A. that can I repair the radio B. whether -I can repair the radio
C. I can repair the radio D. whether can I repair the radio
5. Keep in mind _____.
A. that the teacher said B. what did the teacher say
C. that did the teacher say D. what the teacher said
6. Could you advise me _____?
A. which book should I read first B. what book should I read first
C. that book 1 should read first D. which book I should read first
7. He was criticized for _____.
A. he had done it B. what he had done C. what had he done D. that he had done it
8. Would you kindly tell me _____?
A. how can I get to the Beijing Railway Station
B. how I can get to the Beijing Railway Station
C. where can I get to the Beijing Railway Station
D. whether can I get to the Beijing Railway Station
9. Mrs. Smith was very much impressed by _____.
A. what had she seen in China B. that she had seen in China
C. what she had seen in China D. which had she seen in China
10. We took it for granted ___
A. that they were not coming B. that were they not coming
C. they were coming not D. were they not coining
11. I really don't know _____
A. I should do next B. what should I do next
C. what I should do next D. how I should do next
12. I'm afraid _____.
A. the little girl will have to be operated on
B. that will the little girl have to operate on
C. the little girl will have to operate on
D. that will the little girl have to be operated on
13. She walked up to _____ .
A. where did I stand B. where I stood
C. I stood there D. where I stood there
14. Can you tell me _____?
A. who is that gentleman B. that gentleman is who
C. who that gentleman is D. whom .is that gentleman
15. We'll give you _____.
A. that do you need B. what do you need
C. whatever you need D. whether do you need
16. They want us to know _____ to help us.
A. what can they B. what they can C. how they can D. how can they
17. We must put _____ into practice.
A. what we have learned B. that we have learned
C. that have we learned D. what have we learned
18. Did she say anything about _____?
A. that the work was to be done B. how was the work to be done
C. that was the work to be done D. how the work was to be done
19. He was never satisfied with _____.
A. what she had achieved B. had what she achieved
C. she had achieved D. that she achieved
20. These photographs will show you _____.
A. what does our village look like B. what our village looks like
C. how does our village look like D. how our village looks like
21. Peter insisted _____ he pay the bill.
A. on that B. what C. that D. on which
22. They urged _____ the library open during the vacation.
A. when B. where C. why D. that
23. We wish we could have learned _____ when we were at high school.
A. what you did B. that you had done
C. that what you did D. what did you do
24.1 will describe to you _____ I saw when there.
A. what B. that C. which D./
25. From _____ I should say he is a good worker.
A. what 1 know of him B. that I do know of him
C. what do I know of him D. that do I know of him
26. I will give this dictionary to __ wants to have it.
A. whomever B. anyone C. whoever D. someone
27._____ they will come here hasn' t been decided yet.
A. What B. That C. When D. Where
28. _____ was said here must be kept secret.
A. Who B. The thing C. Whatever D. Where
29. It is still a question _____ we shall have our sports meet.
A. if B. that C. what D. when
30. I'm going anyway. _____ she will go is up to her to decide.
A. If or not B. Whether or not C. If D. That
31. It is strange _____ she have left without saying a word.
A. that B. what C. why D. how
32. It is very clear _____ our policy is a correct one.
A. what B. that C. why D. where
33. _____ Mr Zhang said is quite right.
A. That B. When C. What D. Whether
34. It has been decided _____ he will be sent there.
A. if B. whether C. why D. that
35. It doesn' t matter _____he' s come back or not.
A. if B. whether C. that D. when
36. It's a great pity _____ we won’t be able to finish the task on time.
A. when B. that C. why D. where
37. It happened _____ I wasn't there that day.
A. when B. why C. where D. that
38._____ you have done might do harm to other people.
A. What B. That C. Which D. The things
39. _____ leaves the room last ought to turn oft the lights.
A. Anyone B. The person C. Whoever D.Who
40._____ the 2000 Olympic Games won't be held in Beijing is known to all.
A. Whether B. If C. Whenever D. That
41. _____ fails to see this will make a big mistake.
A. That B. Whoever C. Whether D. Whether or not
42. __ we need more equipment is quite obvious.
A. What B. Whether C. That D. Whatever
43. Has it been announced _____?
A. when are the planes to take off B. that are the planes to take off
C. where are the planes to take off D. when the planes are to take off
44. That is _____ we all support his idea.
A. what B. why C. where D. when
45. That’s _____ we should do.
A. that B. what C. how D. why
46. _____ is troubling me is _____ I don’t understand _____ he said
A. What; that; what B. What; what; what
C. That; that; what D. Why; that; which
47. Things were not _____ they seemed to be.
A. when B. why C. that D. what
48. That’s _____ I want to say.
A. all what B. what C. all which D. what that
49. That’s _____ .
A. where our differences lie B. our differences lie there
C. where do our differences lie D. that where our differences lie
50. That is _____ .
A. where lived he there B. where did he live
C. where he lived D. that where he lived
51. The questions is _____.
A. whether is it worth doing B. that if it is worth doing
C. whether it is worth doing D. if it is worth doing
52. Water will continue to be _____ it is today next in importance to oxygen.
A. how B. which C. what D. as
53. That's_____.
A. how did I become a teacher B. how I became a teacher
C. how a teacher I became D. that I became a teacher
54. They are just _____.
A. that what shall I have B. what shall I have
C. that I shall have what D. what I shall have
55. It looked ____.
A. as if it was going to rain B. that as if it was going to rain
C. as if was it going to rain D. as if that it was going to rain
56. That's_____.
A. how she did it B. that how did she do it.
C. how did she do it D. what she did it
57. That is _____ we decided to put the discussion off.
A. where B. which C. that D. why
58. That’s _____ I lived when I was ten years old.
A. where B. at which C. there where D. when
59. My suggestion is _____ we should send a few comrades to help them.
A. if B. that C. when that D. that where
60. The idea _____ all people are selfish is wrong.
A. what B. that C. why D. if
61. We heard the news _____ our team had won.
A. that B. what C. whether D. why
62. The fact _____ he hadn’t said anything surprised us all.
A. why B. if C. that D. whether
63.I have no idea _____ she will be back.
A. that B. where C. that when D. when
64. We must keep in mind the fact _____ China is still a developing country.
A. whether B. that C. why D. when
65. They have no idea at all _____.
A. where he has gone B. where did he go
C. where has he gone D. which place he has gone