名詞性從句精講
從句是相對於主句而言的,即它是從屬於某一個主句,而不能單獨作一個句子。在英語中,主要有三大從句,即名詞性從句（包括主語從句,賓語從句,表語從句,同位語從句）、形容詞性從句（即定語從句）、副詞性從句（即狀語從句,包括時間、條件、結果、目的、原因、讓步、地點、方式等）。
在句子中起名詞作用的句子叫名詞從句(Noun Clauses）。名詞從句的功能相當於名詞詞組,它在複合句中能擔任主語、賓語、表語、同位語等，因此根據它在句中不同的語法功能，名詞從句又可分別稱為主語從句、賓語從句、表語從句和同位語從句。引導名詞性從句的連接詞可分為三類：
（1）從屬連接：that, whether, if（不充當從句的任何成分）
（2）連接代詞：what, whatever, who, whoever, whom, whose, which.
（3）連接副詞：when, where, how, why
1
主語從句
做句子主語的從句叫主語從句。主語從句通常由從屬連詞that，whether，if和連接代詞what，who，which，whatever，whoever以及連接副詞how，when，where，why等詞引導。that在句中無詞義，只起連接作用；連接代詞和連接副詞在句中既保留自己的疑問含義、又起連接作用，在從句中充當從句的成分。
1. that引導
That he is still alive is a wonder. 他還活著，真是奇蹟。
That we shall be late is certain. 我們要晚了，這是確定無疑的。
That he should have ignored the working class was natural. 他忽視工人階級是很自然的。
That she is still alive is a consolation. 她還活著是使人感到寬慰的。
That she became an artist may have been due to her father’s influence. 她成為畫家可能是受她父親的影響。
That you are coming to London is the best news I have heard this long time. 你將來倫敦是好久以來我聽到的最好消息。
That she was chosen made a tremendous stir in her village. 她被挑選上，在她村子裡引起很大轟動。
2. whether引導
Whether it will do us harm remains to be seen. 是否對我們有害還要看一看。
Whether they would support us was a problem. 他們是否會支持我們還是一個問題。
3. 連接代詞引導
Whoever is top from wins the game when two matched players meet. 兩強相爭勇者勝。
Whichever (of you) comes in first will receive a prize. 無論(你們)誰先到都可以得獎。
Whichever you want is yours. 你要哪個，哪個就是你的。
4. 連接副詞引導
When we arrive doesn’t matter. 什麼時候到沒有關係。
How this happended is not clear to anyone. 這件事怎樣發生的，誰也不清楚。
How many people we are to invite is still a question. 邀請多少人還是一個問題。
5. 關係代詞型what引導
What I want to know is this. 我想知道的就是這一點。
What’s done is done. 事已成定局。
What he says is not important. 他說的話並不重要。
What I am telling you is mere impressions. 我和你說的都不過是一些印象而已。
What you need is a good-sized canvas bag. 你需要的是一個比較大的帆布袋。
6.主語從句與形式主語it
有時為了考慮句子平衡，通常在主語從句處使用形式主語it，而將真正的主語從句移至句末。這分三種情況：
(1) 對於以連詞that引導的主語從句，通常用形式主語代主語從句：
It’s a pity that he didn’t come. 很遺憾他沒來。
It is important that he should know about this. 他必須知道此事。
It’s vital that we be present. 我們出席是至關重要的。
It was intended that you be the candidate. 大家的意圖是讓你當候選人。
It is appropriate that this tax be abolished. 廢除這個稅是恰當的。
It’s unfair that so many people should lose their jobs. 竟有這麼多人失業這是不公平的。
It’s amazing that she should have said nothing about it. 她竟未談及此事令人驚訝。
It’s unthinkable that they should deny my request. 他們竟然拒絕我的請求，這是不可思議的。
That they should refuse to sign the petition required great courage. 他們拒絕在請願書上簽字這是需要很大勇氣的。
(2) 對於以連接代詞(副詞)引導的主語從句，可以使用形式主語代主語從句，也可直接在句首使用主語從句：
Whether they would support us was a problem. 他們是否會支持我們還是一個問題。
It was a problem whether they would support us. 他們是否會支持我們還是一個問題。
It remains to be seen whether it will do us harm or good. 它對我們是利是害，還得看看再說。
(3) 對關係代詞型what引導的主語從句，通常直接將主語從句放在句首。如：
What we need is money. 我們需要的是錢。
What I want to know is this. 我想知道的就是這一點。
★如果句子是疑問句，則必須用帶形式主語it的結構：
Is it true that he is the girl’s father? 他是那女孩的父親，是真的嗎？
How is it that you are late again? 你怎麼又遲到了？
7.連詞that的省略問題
引導主語從句的連詞that 有時可省，有時不能省，其原則是：
若that引導的主語從句直接位於句首，則that不能省略；若that引導的主語從句位於句末，而在句首使用了形式主語it，則that可以省略。
如：That you didn’t go to the talk was a pity. 很遺憾你沒去聽報告。(that不可省)
It was a pity (that) you didn’t go to the talk. 很遺憾你沒去聽報告。(that可省)
8. 另外注意在主語從句中用來表示必須、理應如此、建議、要求等語氣時，謂語動詞要用虛擬語氣“(should) +do”
常用的句型有：
It is necessary (important, natural, strange, etc.) that …
It is suggested (requested, proposed, desired, etc.) that…
2
賓語從句
在複合句中用作賓語的從句叫賓語從句。引導賓語從句的連接詞與引導主語從句連接詞大致一樣。
1.賓語從句中引導詞用法
在複合句中做主句的賓語，引導詞有：
連詞：that (that 常可省略),whether, if
代詞：who, whose, what ,which
副詞：when ,where, how, why 等。
①連詞：
He told me (that he would) go to the college the next year 他告訴我他明年上大學。
I don’t know if there will be a bus any more. 我不知道是否還會有公交車。
Nobody knew whether he could pass the exam. 沒有人知道他是否會通過考試。
❶that引導
（在非正式場合that可以省略）
★可跟that引導的從句做賓語的動詞有：say, think, insist, wish, hope, demand, imagine, wonder, know, suppose, see, believe, agree, admit, deny, expect, explain, order, command, feel, dream, suggest, hear, mean, notice, prefer, request, require, propose, declare, report等。
如：The boy believes that he will travel through space to other planets.
★賓語從句的否定轉移
當主句謂語動詞是 think, believe, suppose, expect 等詞，而賓語從句的意思是否定時，常把否定轉移至主句表示。並且主句的主語是第一人稱而且為一般現在時,從句的否定詞一般要轉移到主句上來,其反義疑問句一般與賓語從句一致。
I don’t think it is right for him to treat you like that.
I don’t believe that man is killed by Jim ,is he?
I expect our English teacher will be back this weekend, won't she/he?
We suppose you have finished the project, haven't you?
如果賓語從句中有某個含有否定意義的形容詞或副詞(不包含帶有否定前綴的詞，如：unhappy，unfair，dislike等),其反義疑問句要用肯定形式。
We find that he never listens to the teacher carefully, does he?
我們發現他從不仔細聽老師講課，是不是？
★當主句的主語是第二、三人稱時，其反義疑問句一般與主句保持一致。
Your sister supposes she needs no help, doesn't she?
You thought they could have completed the project, didn't you?
They don't believe she's an engineer, do they?
She doesn't expect that we are coming so soon, does she?
★在以下情況中that不能省略
（1）當句中的動詞後接多於兩個由that引導的賓語從句時，第一個that可省，但後面的that不可省。
I believe（that）you have done your best and that things will get better．
（2）當主句的謂語動詞與that賓語從句之間有插入語時，that一般不可省。
Just then I noticed, for the first time, that our master was wearing his fine green coat and his black silk cap.
（3）當that從句是雙賓語中的直接賓語時，that不可省。
I can’t tell him that his mother died.
（4）當it作形式賓語時
例句：She made it clear that she had nothing to do with him．
許多帶複合賓語的句子，that引導的賓語從句經常移到句子後部，而用it作形式賓語。
（5）當賓語從句前置時 That our team will win，I believe．
（6）當that作learn, suggest ,explain ,agree ,wonder ,prove ,mean, state ,feel ,hold等動詞的賓語時;
❷由whether,if
當由一般疑問句充當賓語從句時，用if或whether引導，意為“是否”。
如：I don't know if ／whether he still lives here after so many years．我不知道這麼多年後他是否還住在這兒。
但在下列情況下只能用whether，不能用if：
①在具有選擇意義，又有or或or not時，尤其是直接與or not連用時，往往用whether（if…or not也可以使用）。
如：Let me know whether ／if he will come or not．
（＝Let me know whether or not he will come）讓我知道他是否能來。
I don't know whether ／if he does any washing or not．
（＝I don't know whether or not he does any washing．）我不知道他洗不洗衣服。
I wonder whether we stay or whether wego．我不知道我們是去還是留。
②在介詞之後用whether。
如：I'm interested in whether he likes English．我關心的是他是否喜歡英語。
We're thinking about whether we can finish the work on time．我們正在考慮是否能按時完成這項工作。
③在不定式前用whether。
如：He hasn't decided whether to visit the old man．他尚未決定是否拜訪那位老人。
He hasn't decided whether to go by bus or by train．他還未決定是乘公共汽車去還是坐火車去。
④whether置於句首時，不能換用if。
如：Whether this is true or not，I can't say．這是否是真的我說不上來。
⑤引導主語從句和表語從句時宜用whether。
如：Whether she will come or not is still a question．她是否能來還是個問題。
⑥若用if會引起歧義時，則用whether。
如：Please let me know if you like the book．
可理解為：If you like the book，please let me know．你如果喜歡這本書，請告訴我。
❸只能用if不能用whether引導
（1）if引導條件狀語從句，意為“如果”
The students will go on a picnic if it is sunny.
（2）if引導否定概念的賓語從句時
He asked if I didn’t come to school yesterday.
（3）引導狀語從句even if（即使）和as if（好像）時
He talks as if he has known all about it.
②連接代詞和連接副詞引導的賓語從句
這樣的賓語從句實際上是由特殊疑問句變化而來的，賓語從句要用陳述句語序。用於這種結構的動詞常常是：see, say, tell, ask, answer, know, decide, show, find out, imagine, suggest, doubt, wonder, discover, understand, inform, advise等。
❶連接代詞
Who ,whom ,whose ,which ,what,在句中擔任主語、賓語、定語或者表語。連接代詞一般指疑問,但what, whatever除了指疑問外,也可以指陳述.
Do you know who has won Red Alert game?
你知道是誰贏得了紅色警報的遊戲麼？
The book will show you what the best CEOs should know.
這本書會告訴你最好的執行總裁該瞭解什麼.
❷連接副詞
When ,where ,why ,how，在句中擔任狀語的成分。
He didn’t tell me when we should meet again. 他沒有告訴我什麼時候我們能再見面。
Could you please tell me how you use the new panel?
你能告訴我怎麼用這個新的操作盤嗎?
None of us knows where these new parts can be bought.
沒有人知道這些的新的零件能在哪裡買到。
2.賓語從句的語序
賓語從句的語序是陳述句語序即：連接代詞/副詞+主語+謂語+其他成分。
I don’t know what they are looking for.
Could you tell me when the train will leave?
3.賓語從句的時態
（1）時態：主句是一般現在時，從句根據實際情況使用任何時態。
例句：The headmaster hopes everything goes well.
（2）主句是過去時態，從句須用過去時態的某種形式。
例句：She was sorry that she hadn’t finished her work on time.
（3）當賓語從句表示的是一個客觀真理或者事實時，即使主句是過去時，從句也用一般現在時態。
例句：The teacher told his class that light travels faster than sound.
★注意：運用虛擬語氣的情況在表示“建議 suggest 、advise、propose; 要求demand 、desire、request；決定 decide; 命令 order、command、require; 堅決主張 insist”等動詞後跟賓語從句，用（should）+v．（虛擬語氣）
如：I suggested that you（should）study hard．
He ordered that we should go out at once．
虛擬語氣用在賓語從句中：動詞 wish, suggest ,order ,insist , propose,等詞後面的賓語從句表示的是一種虛擬語氣，賓語從句中的動詞動作表示的只是一種願望、要求。
如：I wish she would be on my side. 我希望她能站在我一邊。
I wish I could help him. 我希望我能幫助他。
He insisted that all of us should be there on time by any means. 他堅持要我們大家想盡辦法按時去那兒。
動詞 demand, suggest, order, insist, propose 後面的從句中，"should" 可以省略。
如：The teacher suggested that we (should) clean the blackboard after class. 老師建議我們課後把黑板擦了。
He ordered that the students wash the clothes every week by themselves. 他要求學生每週都要自己洗衣服。
4.簡化賓語從句的方法
把含有賓語從句的複合句轉化為簡單句，使其與原句意思相同（或相近）的試題。下面就介紹幾種常用的簡化賓語從句的方法：
（1）當主句謂語動詞是hope， decide， wish， choose， agree， promise等，且賓語從句的主語與主句主語一致時，賓語從句可簡化為不定式結構。例如：
Li Ming hopes he will be back very soon.
→Li Ming hopes to be back very soon.
We decided that we would help him.
→We decided to help him.
（2）當主句謂語動詞是know， learn， remember， forget， tell等動詞，且主句主語與從句主語一致時，賓語從句可簡化為“疑問詞+不定式”結構。
例如：
She has forgotten how she can open the window.
→She has forgotten how to open the window.
★注：當主句謂語動詞是tell， ask， show， teach等動詞，且後帶雙賓語，從句主語和間接賓語一致時，賓語從句可簡化為“疑問詞+不定式”結構。例如：
Could you tell me how I can get to the station？
→Could you tell me how to get to the station？
（3）當主句的謂語動詞是order（命令），require（需要）等時，如果主句和從句的主語不一致，賓語從句可簡化為“名詞（代詞）+不定式”結構。例如：
The headmaster ordered that we should start at once.
→The headmaster ordered us to start at once.
（4）某些動詞後的賓語從句，可以用介詞加動名詞（短語）等其他形式簡化。例如：
He insisted that he should go with us.
→He insisted on going with us.
The poor boy doesn’t know when and where he was born.
→The poor boy doesn’t know the time and the place of his birth.
（5）某些動詞後面的賓語從句可轉化為“賓語+V-ing形式（作賓語補足語）”結構。例如：
Liu Ping found that there was a wallet lying on the ground.
→ Liu Ping found a wallet lying on the ground.
（6）動詞seem後的賓語從句，也可以用不定式（短語）來簡化，但句型需要進行適當的變化。例如：
It seemed that the boys were going to win.
→The boys seemed to win.
★除上述方法外，還有一些特殊句式的轉化。
例如：
I found that it was difficult to learn English well.
→I found it difficult to learn English well.
Soon we found that the ground was covered with thick snow.
→Soon we found the ground covered with thick snow.
They found that the box was very heavy.
→They found the box very heavy.
3
表語從句
表語：說明主語的性質、特徵、狀態或身份，說明主語是什麼或者怎麼樣。總之表語是對主語的解釋和說明，是主語具體化，並且常與連繫動詞一起使用。
表語從句：在複合句中作表語的從句, 就叫做表語從句。表語從句一般放在系動詞之後,結構是“主語+系動詞+表語從句”。
★連繫動詞：be動詞、表示持續的系動詞（keep, remain, stay）、感官動詞feel(摸起來，感覺) , smell(聞起來) , sound(聽起來) , taste(嚐起來，吃起來) 等、表示變化的系動詞（become, grow, turn, fall, get, go,）、表終止的系動詞prove, turn out(結果是，證明是)、seem, appear（看起來……）
連繫動詞通常不用於被動語態和進行時態中。
He has become what he wanted to be ten years ago.
他已經成為了他10年前想成為的樣子。
His suggestion is that we should stay calm.
他的建議是，我們應該保持冷靜。
1.表語從句的引導詞
①從屬連詞
that / whether /as if /as though/as/because
(1) that引導表語從句本身沒有詞義，在句中只起連接作用，不充當句子成分，一般不能省略。
That fact is that more than seventy percent of the earth’s surface is covered by water.
連接詞that一般不能省略，但當主句中含動詞do的某種形式時，that可以省略。
What I want to do is (that) I can go up to him and thank him. 我想做的事是走到身邊去感謝他。
(2) whether引導表語從句表示“是否”,但不充當句子的成分。
The question is whether we can finish our work by tomorrow evening.
if 與whether均意為“是否”，但引導表語從句時，只能用whether, 不能用if。
(3)as if/though“好像”，引導表語從句時要注意語態。
如果句中的情況與事實不相符，從句多用虛擬語氣。如果從句表示與現在事實相反,謂語動詞用一般過去式；如果從句表示與過去事實相反時,謂語動詞要用“had + 過去分詞 ”，如果從句表示將來的可能性不大，用would (might ,could )+動詞原形。
Li Lei is now in a new jacket. He looks as if he were an American boy. (現在事實相反)
The girl is giving us a vivid description of the moon. It seems as if she had been to the moon many times. （與過去事實相反）
It looks as if it might rain. （與將來事實相反）
但是，如果as if/though引導的表語從句所表示的與事實相符，從句則用陳述語氣。
The clouds are gathering. It looks as if is going to rain.
(4) as引導表語從句
He looked just as he had looked ten years before.
他看起來還與十年前一樣。
(5) because引導表語從句
常用結構：This/That/It is/was because...
That is because I don’t like Chinese.
②連接代詞
who/whom/whose/what/which/whoever/whatever/whichever/whomever，在表語從句中做主語、賓語、表語和定語。
Tom is no longer what he used to be. (what做表語)
The problem is who is fit for this job. (who做主語)
This is what I want to tell you. (what做賓語)
The problem is whose work is the best. (whose做定語)
③連接副詞
when/where/how/why，在表語從句中做狀語。
The question is how he did it. 問題是他是如何做此事的。
The question is where we can live.問題是我們能住在哪兒。
2.特例強調
（1）reason做主語或主語中包含事件的起因時,後面的表語從句表示原因時要用that來引導,而不用because；why引導主語從句做主語時，表語從句用that引導，不用because。
The reason is that he got up late.
Why he is late is that he got up late.
（2）that is why/because
①That is why ...是常用句型,其中why引導的從句在句中作表語,該句型通常用於針對前面已經說過的原因進行總結。That is the reason why ...與That is why ...是同義的，“這就是……的原因/因此……”，但是從語法結構上講That is the reason why ...中的why引導的是一個定語從句。
That is why she failed to pass the exam.
那就是她考試不及格的原因。(why 在表語從句中充當原因狀語)
That is the reason why she failed to pass the exam.
那就是她考試不及格的原因。(why 在定語從句中充當原因狀語)
②That is because...句型中從屬連詞because引導的名詞性從句在此作表語，這也是個常用句型，意為“這就是因為……”。
That is because I got up late. 這是因為我起床遲了。
③“That is because...”與“That is why...”之間的不同在於“That is because...”指原因或理由， “That is why...”則指由於各種原因所造成的後果。
I was angry. That was because he didn’t understand me.我生氣是因為他不理解我。(表語從句強調原因)
That’s why he got fired from that firm.那正是他被公司解僱的原因。(表語從句強調結果)
（3）The reason (why.../for...)is /was that... “...的原因是...”
The reason for his absence is that he got up late.
The reason why he is absent is that he got up late.
他缺席的原因是他起床遲了。
（4）使用虛擬語氣的表語從句
在表示建議、勸告、命令、計劃含義的名詞後的表語從句，謂語動詞需用“should+動詞原形”表示虛擬語氣，should可省略。常見的詞有：advice，suggestion，order，request，proposal，plan，idea等。
My suggestion is that we （should） start early tomorrow.我的建議是我們明天一早就出發。
4
同位語從句
在複合句中充當同位語的名詞性從句稱為同位語從句。一個名詞（或其它形式）對另一個名詞或代詞進行補充說明，這個名詞（或其它形式）就是同位語。
1.用法
同位語從句一般跟在某些名詞後面，用以說明該名詞表示的具體內容。
I heard the news that our team had won．我聽到了我們隊獲勝的消息。
①可以跟同位語從句的抽象名詞通常有news，idea，fact，promise，question，doubt，thought，hope，message，suggestion，word（消息），possibility等。
I’ve come from Mr. Wang with a message that he won’t be able to see you this afternoon．
我從王先生那裡來，他讓我告訴你他今天下午不能來看你了。
②在某些名詞表“建議，命令，要求等”（如demand, wish, suggestion, resolution等）後面的同位語從句要用虛擬語氣 （即should+動詞原形；should可省）。
There was a suggestion that Brown should be dropped from the team.
有一項建議是布朗應該離隊。
③同位語從句前名詞的數：同位語從句前的名詞通常用單數形式，並且往往帶有限定詞(word除外)加以修飾。
Where did you get the idea that I could not come？你在哪兒聽說我不能來？
2.連詞
英語中引導同位語從句的詞通有that，whether，連接代詞what，who，連接副詞how, when, where等。（注：if, which 不能引導同位語從句。）
（1）連詞that引導同位語從句（注：引導同位語從句的that不能省略）
The idea that you can do this work well without thinking is quite wrong.
你認為不動腦筋就能做好這件工作的想法是完全錯誤的。（作idea的同位語）
【注意】引導同位語從句的連詞that通常不省略。
（2）連詞whether引導同位語從句（注：if不能引導同位語從句）
The question whether we should call in a specialist was answered by the family doctor.
我們是否請專家由家庭醫生來定。
He must answer the question whether he agrees to it or not.
他必須回答他是否同意這樣一個問題。
（3）其它引導詞引導的同位語從句
A.連接代詞
what, who, whom, whose引導同位語從句
I have no idea what size shoes she wears.我不知道她穿幾號的鞋。（what作定語）
The question who will take his place is still not clear.（who作主語）
B.連接副詞
when, where, how, why 引導同位語從句
We haven’t yet settled the question where we are going to spend our summer vacation.
到哪兒去度暑假，這個問題我們還沒有決定。
l have no idea when he will be back．我不知道他什麼時候回來。
My question how I shall get in touch with him has not been answered.
3.分隔式同位語從句
有時同位語從句可以不緊跟在說明的名詞後面，而被別的詞隔開。在語法上叫做分隔式同位語從句。
The thought came to him that maybe the enemy had fled the city．
他突然想起可能敵人已經逃出城了。
Several years later，word came that Napoleon himself was coming to inspect them． 幾年以後，有消息傳來說拿破崙要親自視察他們。
4.定語從句與同位語從句
同位語從句是用於說明所修飾名詞的具體內容的，它與被修飾詞語通常可以劃等號；而定語從句是限制所修飾名詞的，它的作用是將所修飾的名詞與其他類似的東西區別開來。
同位語從句中的引導詞that不做成分，而定語從句中的引導詞that做成分。
定語從句中，關係代詞做賓語可以省略；同位語從句的引導詞不可以省略。
We are glad at the news that he will come. 聽到他要來這個消息我們很高興。
We are glad at the news that he told us. 聽到他告訴我們的這個消息我們很高興。
知識來源與網絡！
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