關于英語語法的主語從句
在學習、工作或生活中，大家一定沒少看到經典的句子吧，在不同類型的文章里，不同位置的句子的作用也是不同的。什么樣的句子才經典呢？以下是小編整理的英語語法的主語從句，供大家參考借鑒，希望可以幫助到有需要的朋友。
英語語法的主語從句 1
1.以what等連接代詞引導的主語從句
What you need is more practice. 你需要的是更多的練習。
Whoever wants it may have it. 誰要都可以給他。
同類的連接代詞還有：What, who, whom, whose, which, whatever, whoever, whichever
2.以that, whether從屬連詞引導的主語從句
It was strange that he had made a mistake. 真奇怪，他竟然錯了。
That we need more equipment is quite obvious. 我們需要更多的設備，這是很明顯的。
Whether he will join us won't make too much difference.
他是否加入我們，沒有太大的差別。
3.主語從句的引導詞that什么時候可以省略
當主語從句不太長時，引導詞“that”可以省略
It's clear (that) he has done his best. 很明顯他已經盡力而為了。
It's a wonder (that) he didn't fail. 真奇怪，他沒有失敗。
4.以when等連接副詞引導的主語從句
When they will come hasn't been made public. 他們什么時候來還沒有公布。
Where she has gone is not known yet. 她去了哪兒，還不知道。
Why he did it will remain a puzzle for ever. 為什么他做那件事將永遠是個謎團。
5.虛擬語氣：主語從句
形容詞為necessary, important, impossible, strange, natural, essential時，在“It + be + 形容詞或過去分詞 + 主語從句”中，主語從句要虛擬。
It is necessary that the problem (should) be discussed at once.
立刻討論這個問題很有必要。
It is strange that he (should) have so many friends. 太奇怪了，他有那么多的朋友。
6.主語從句與強調句的區別
注意事項：
1). 在主語從句中，把It was … that去掉之后，就已經完全不像一個句子了。
2). 在強調句中，把It was … that去掉之后，還基本上像個句子。
3). 主語從句有以下的引導詞：what, who, whom, whose, which, whatever, whoever, whichever
4). 強調句的引導詞只有：that, who。
主語從句：
It was strange that he had made a mistake. 如果把，It was … that 去掉以后，剩下strange he had made a mistake.就不算是句子了。
It is immaterial where or when he goes. 他去何處或者何時去是無關緊要的'。
It is said that…, 和It is reported that…這樣的結構，后面接的是主語從句：
It is said that he’s got married. 聽說他已經結婚了。
強調句：
It was she that had been wrong. 錯的是她。（強調主語）如果把，It was … that 去掉以后，剩下she had been wrong.還勉強算的上是一個句子。
It was this novel that they talked about last night. 他們昨晚談論的是這部小說。（強調賓語）
It was in London that I first saw her. 我是在倫敦第一次見到她的。（強調地點狀語）
英語語法的主語從句 2
主語從句是在復合句中充當主語的從句，通常放在主句謂語動詞之前或由形式主語it代替，而本身放在句子末尾。
1. It 作形式主語和it引導強調句的比較
It 作形式主語代替主語從句，主要是為了平衡句子結構，主語從句的連接詞沒有變化。而it引導的強調句則是對句子某一部分進行強調，無論強調的是什么成分，都可用連詞that。被強調部分指人是也可用who/whom。例如： It is a pity that you didn’t go to see the film. It doesn’t interest me whether you succeed or not. It is in the morning that the murder took place. It is John that broke the window.
2. 用it 作形式主語的結構
(1) It is ＋名詞＋從句 It is a fact that … 事實是… It is an honor that …非常榮幸 It is common knowledge that …是常識
(2) it is ＋形容詞＋從句 It is natural that… 很自然… It is strange that… 奇怪的是…
(3) it is ＋不及物動詞＋從句 It seems that… 似乎… It happened that… 碰巧…
(4) it ＋過去分詞＋從句 It is reported that… 據報道… It has been proved that… 已證實…
3. 主語從句不可位于句首的五種情況
(1) if 引導的主語從句不可居于復合句句首。
(2) It is said , (reported) …結構中的主語從句不可提前。例如： It is said that President Jingo will visit our school next week. (right) That President Jiang will visit our school next week is said. (wrong)
(3) It happens…, It occurs… 結構中的`主語從句不可提前。例如： It occurred to him that he failed in the examination. (right) That he failed in the examination occurred to him. (wrong)
(4) It doesn’t matter how/whether …結構中的主語從句不可提前。例如： It doesn’t matter whether he is wrong or not. (right) Whether he is wrong or not doesn’t matter. (wrong)
(5) 含主語從句的復合句是疑問句時，主語從句不可提前。例如： Is it likely that it will rain in the evening? (right) Is that will rain in the evening likely? (wrong)
4. What 與that 在引導主語從句時的區別
What 引導主語從句時在句時在從句中充當句子成分，如主語．賓語．表語，而that 則不然。例如：
1) What you said yesterday is right.
2) That she is still alive is a consolation.
英語語法的主語從句 3
即在復合句中充當主語成分的句子，例如"That he finished writing the composition in such a short time surprised us all"，他在很短的時間內寫完作文讓我們都很驚訝，此復合句主要描述的是某事讓我們驚訝，某事就是該復合句的主語，因此“That he finished writing the composition in such a short time”便是該復合句的主語從句。
引導主語從句的連詞主要有：
從屬連詞：that whether
連接代詞：who whoever whom whose what whatever which whichever
連接副詞：when where how why
定義：在復合句中充當主語成分的句子叫做主語從句。
主語從句的時態不受主句時態的影響和限制
（1）That he finished writing the composition in such a short time surprised us all.
（2）Whether we will go for an outing tomorrow remains unknown.
（3）Who will be our monitor hasn't been decided yet.
（4）Whom we must study for is a question of great importance.
（5）What caused the accident remains unknown.
（6）Whatever you did is right.
（7）Whom the watch belongs to is unknown.
（8）What we need is time.
（9）What we need are good doctors.
名詞性從句的時態規則：
1）、主句謂語動詞是現在或將來時，從句謂語動詞可以用任何需要的時態。
I wonder what he is doing now.
Do you know when and where he was born?
I'll write to tell him where I 'll meet him.
2）、主句謂語動詞是過去時，從句謂語動詞一般需用過去時。
（1）從句與主句的謂語動作同時發生，從句用一般過去時或過去進行時。
I thought that he studied hard.
He told me his son was watching TV.
（2）從句謂語動作在主句謂語動作之后，從句用過去將來時。
He said he would spend his holidays in Qingdao.
（3）從句謂語動作在主句謂語動作之前，從句用過去完成時。
They told me they had waited for me half an hour.
（4）從句如果有表示過去某一具體時間的狀語，仍用過去時。
She told me her brother died in 1945.
3)客觀的條件，從句時態不受絲毫影響。
（1）從句說明的是不受時間限制的事實或真理（客觀真理）。
The teacher told us that the earth turns from west to east.
He said Asia is the largest continent.
It was true that water freezes at thirty-two degrees Fahrenheit.
（2）當從句表示的是反復出現的時態不變。
She told me that she gets up at six o'clock every morning.
He asked me when the train usually starts.
（3）當從句是用來表達解釋科技內容時時態不變。
（4）當從句的謂語動作仍在繼續時，或者表示現在仍在的狀態時，時態不變。
He said that the workers in that factory are trying to fulfill the task in time.
She told me the other day that she is only 10.
（5）當從句的動作狀態還未發生，要用一般式表示。強調與現在的聯系。
He said he will wait for me this evening.
小結:
（1）引導主語從句連詞有that,whether,who,what,whatever等
（2）連詞位于句首不能省略
（3）主語從句大多數情況下視為第三人稱單數，但也有例外；
注意：當what引導的名詞性分句作主語時，主謂一致問題極為復雜。著名學者周海中教授在論文《關于what-分句作主語的主謂一致問題》中就這一問題做了深入研究，并給出了10種的主謂一致關系。這些一致關系值得英語學習者和使用者特別注意。
定語從句
一個簡單句跟在一名詞或代詞后（先行詞）進行修飾限定，就叫做定語從句。在主句中充當定語成分。被修飾的`詞叫先行詞。定語從句不同于單詞作定語的情況，它通常只能放在被修飾的詞（即先行詞）之后。
定語 從句由關系詞（關系代詞、關系副詞）引導，關系代詞、關系副詞位于定語從句句首。
關系代詞引導的定語從句
關系代詞所代替的先行詞是人或物的名詞或代詞，并在句中充當主語、賓語、定語等成分。關系代詞在定語 從句中作主語時，從句謂語動詞的人稱和數要和先行詞保持一致。
1）who, whom,that
這些詞代替的先行詞是人的名詞或代詞，在從句中所起作用如下：
Is he the man who/that wants to see you?
他就是想見你的人嗎？（who/that在從句中作主語） He is the man whom/ that I saw yesterday.
他就是我昨天見的那個人。（whom/that在從句中作賓語）
2) Whose 用來指人或物，(只用作定語, 若指物，它還可以同of which互換）, 例如：
They rushed over to help the man whose car had broken down. 那人車壞了，大家都跑過去幫忙。
Please pass me the book whose (of which) cover is green. 請遞給我那本綠皮的書。
3）which, that
它們所代替的先行詞是事物的名詞或代詞，在從句中可作主語、賓語等，例如：
A prosperitywhich / thathad never been seen before appears in the countryside. 農村出現了前所未 有的繁榮。（which / that在句中作主語）
The packagewhich / thatyou are carrying is about to come unwrapped. 你拿的包快散了。(which / that 在句中作賓語）
關系副詞引導的定語從句
關系副詞可代替的先行詞是時間、地點或理由的名詞，在從句中作狀語。
1）when, where, why
關系副詞when, where, why的含義相當于"介詞+ which"結構，因此常常和"介詞+ which"結構交替使用，例 如：
There are occasions when (on which) one must yield. 任何人都有不得不屈服的時候。
Beijing is the place where (in which) I was born.北京是我的出生地。
Is this the reason why (for which) he refused our offer? 這就是他拒絕我們幫助他的理由嗎？
2）that代替關系副詞
that可以用于表示時間、地點、方式、理由的名詞后取代when, where, why和"介詞+ which"引導的定語從 句，在非正式文體中that常被省略（正式文體中不可省略），例如：
His father died the year (that / when / in which) he was born. 他父親在他出生那年逝世了。
He is unlikely to find the place (that / where / in which) he lived forty years ago. 他不大可能找到他四十 年前居住過的地方。
判斷關系代詞與關系副詞
方法一： 用關系代詞，還是關系副詞完全取決于從句中的謂語動詞。及物動詞后面無賓語，就必須要 求用關系代詞。例如：
（錯） This is the mountain village where I visited last year.
（錯） I will never forget the days when I spent in the countryside.
（對） This is the mountain village (which) I visited last year.
（對） I'll never forget the days (which) I spent in the countryside.
習慣上總把表地點或時間的名詞與關系副詞 where, when聯系在一起。此兩題錯在關系詞的誤用上。
方法二： 準確判斷先行詞在定語從句中的成分(主、謂、賓、定、狀)，也能正確選擇出關系代詞/關系 副詞.先行詞在從句中作主、定、賓語時，應選擇關系代詞；先行詞在從句中作狀語時，應選 擇關系副詞。
例如：（對）Is this the museum which you visited a few days ago?
（對）Is this the museum where the exhibition was held?
從句結構
定語從句公式
定語從句=先行詞+關系詞+從句
先行詞
指被定語從句修飾的名詞、代詞或句子。
一般先行詞出現在定語從句的前面。
關系詞
關系詞常有3個作用：
①連接作用，連接主句和定語從句。
②指代先行詞。
③在定語從句中擔當成分。
注：關系代詞有主語、賓語、定語之分。一般who做主語或其賓格形式的whom做賓語(whom作賓語時可省略），whose作為定語（whose不可省略）。關系代詞在從句中作主語，賓語，定語等，關系副詞在從句中作地點狀語（where），時間狀語（when），原因狀語（why）。[1]
定語用來限定、修飾名詞或代詞，是對名詞或代詞起修飾、限定作用的詞、短語（動詞不定式短語、動名詞表示的）漢語中常用“……的”表示。主要由形容詞擔任，此外，名詞、代詞、數詞、分詞、副詞、不定式以及介詞短語也可以來擔任，也可以由一個句子來擔任。單詞作定語時通常放在它所修飾的詞之前，作前置定語。短語、從句作定語時則放在所修飾的詞之后，作后置定語。
被定語從句修飾的名詞、代詞稱為先行詞。如“the girl”，“the book”
如:She is the girl who likes singing. 她就是那個喜歡唱歌的女孩。
這就是一個定語從句。
英語語法的主語從句 4
一、定義 ：
在復合句中起主語作用的從句叫做主語從句。
二、位置：
一般與陳述句基本結構中的主語相同。但多數情況下用it做形式主語，而把主語從句放在主句之后，避免頭重腳輕。
三、主語從句的種類
(1) 由連詞that引導的主語從句。
例如：That you will win the medal seems unlikely.
你想獲得獎牌看起來是不可能的。
That you are so indifferent bothers me.
你如此冷淡使我很煩惱。
That she survived the accident is a miracle.
她在事故中幸免于難簡直是奇跡。
(2) 用連接代詞或連接副詞if, whether 引導的主語從句。
例如： Which of them escaped from the prison is still a mystery.
他們哪一個是從監獄里逃跑的，仍然是個謎。
When they will come hasn’t been made pubic.
他們什么時候來還不知道。
Whether she is coming or not doesn’t matter too much.
她來不來都無關緊要。
(3) 用關系代詞引導的主語從句。
例如：What you need is more practice.
你所需要的是更多的訓練。
What I want to know is this. 我想知道的就是這事。
Whatever we do is to serve the people.
我們無論做什么都是為人民服務。
主語從句可以直接放在主語位置上，也可以用it作形式主語，
而將從句放在句末(尤其是當謂語較短時)。
例如：That light travels in straight lines is knownto all.
光沿直線傳播，這是眾所周知的事。
=It is known to all that light travels in straight lines.
眾所周知光沿直線傳播。
When the plane is to take off has not been announced .
飛機何時起飛還沒有宣布。
= It has not been announced when the plane is to take off.
還沒有宣布飛機何時起飛。
當what引導的主語從句表示“…的.東西”時，一般不用it作形式主語。
錯:It is a book what he wants.
對:What he wants is a book. 他想要的是本書。
如果帶主語從句的句子是疑問式，則必須用it作形式主語的結構。
例如：Has it been settled who will be sent to carry outthe task ?
誰將被派去執行這項任務決定了嗎 ?
四、主語從句常用結構
(1) It is + 名詞 + 從句
It is a fact that… 事實是……
It is good news that … ……是好消息
It is a question that … ……是個問題
It is common knowledge that … ……是常識
類似的名詞還有：a pity;a wonder;a good thing; no wonder; surprise等。
例如：It is a mystery to me how it all happened.
這一切是怎么發生的是個謎。
It is common knowledge that the whale is not a fish.
鯨魚不是魚，這是常識。
It is no surprise that Bob should have won the game.
鮑勃會贏得這場比賽，這不足為奇。
(2) It is + 形容詞 + 從句
It is necessary that … 有必要……
It is clear that … 很清楚……
It is likely that … 很可能……
It is important that … 重要的是……
類似的形容詞還有：strange; natural; obvious; true; good;wonderful; possible; unlikely; quite; unusual; certain; evident; worth-while;surprising; interesting; astonishing, etc.
例如：It is obvious that conductors and insulators areboth important in industry.
很明顯導體和絕緣體在工業中都很重要。
It is doubtful whether she will be able to come.
她是否能來令人懷疑。
It was really astonishing that he refused to talk to you .
他拒絕和你說話真是令人驚訝。
It is essential that he should be here by the weekend .
周末之前，他應該到這里是必要的。
It seems obvious that we can not go on like this.
很明顯我們不能這樣下去了。
(3) It is + 過去分詞 + 從句
It is said that … 據說……
It is reported that … 據報道……
It has been proved that … 已證明……
It must be proved that… 必須指出……
類似的過去分詞還有：known; estimated; expected; believed;thought; hoped; noted; discussed; required; decided; suggested; demanded; madeclear; found out,etc.
例如：It is thought that he is the best player.
大家都認為他是最好的選手。
It is estimated that the vase is 2000 years old.
據估計這個花瓶有2000年的歷史。
It is used to be thought that a new star must be due to a collision between twostars. 過去一直認為新星是由于兩顆星星之間碰撞產生的。
It has not been made clear when the new road is to be opened to traffic.
還沒弄清楚這條路將開始通車。
(4) It + 不及物動詞 + 從句
It seems that … 好像是……
It happened that… 碰巧……
It follows that … 由此可見……
It has turned out that … 結果是……
類似的不及物動詞還有：seem, appear, occur, follow, happen, turnout, etc.
例如：It turned out that nobody remembered the address.
結果是無人記得那個地址。
It now appears that they are in urgent need of help.
看起來他們急需幫助。
It does not matter if I missed my train, because there is another later.
沒有趕上這趟火車沒有關系，稍晚還有一趟。
It happened that I saw him yesterday.
碰巧我昨天看見他了。
當“及物動詞 + 賓語”較短時，也可用這種結構。
例如：It shocked me that Peter did not tell anybody wherehe was.
讓我吃驚的是彼得沒有告訴任何人他在哪里。
It does not interest me whether you go or not.
我對你去不去不感興趣。
It +某些固定結構+ 主語從句。
例如：It doesn’t make too much difference (It doesn’t make any difference / It doesn’t alter the situation)，whether it rains or not . 下不下雨都沒有多大關系。
It does not make any difference whether it rains or not .
下不下雨沒什么分別。
It does not make the least difference to me what you do.
對我來說你做什么都無關緊要。
Is it of much consequence to you that Mr. Wang has failed to do it ? 王先生沒有做成這件事對你有什么重要影響嗎?
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