在復合句中，充當賓語的成分是一個句子，這個句子代替了原來用一個詞表示的賓語，稱之為賓語從句。置于動詞、介詞等詞性后面，在句子中起賓語用途的從句叫做賓語從句。在英文學習的時候，這部分語法內容要好好來學習。
具體結構為：主句+引導詞+賓語從句
譬如：
簡單句：We knew that.
復合句：We knew that we should go home.
賓語從句分為三類：動詞的賓語從句，介詞的賓語從句和形容詞的賓語從句。
謂語動詞、介詞、動詞不定式，v.-ing形式后面都能帶賓語從句，有的形容詞之后也可以帶賓語從句。
賓語從句過"三關"：語序，引導詞，時態。
動詞、介詞、形容詞后的賓語從句
1)動詞+賓語從句
We knew that we should go home.
這種動詞一般是及物動詞，即后面能直接加賓語的動詞，譬如：give, tell 等。
但像"arrive"就不可以直接加賓語，假如要加賓語，后面需要加介詞。
2)介詞+賓語從句
They are talking about whether it will rain tomorrow.
容易見到介詞：in, at, on 等等。
3)形容詞+賓語從句
I am sure that he can come on time.
后面可以直接加賓語從句的形容詞有：
pleased, glad, happy, afraid, surprised, certain, sorry等。
語序
無論主句是陳述句還是疑問句，賓語從句都需要用陳述語序，即“主句+連接詞+賓語從句”句式。
依據連接詞在從句中所擔任的不同成分，可分為以下四種：
1)連接詞+謂語。連接詞在從句中作主語。容易見到的連接詞有: who, what, which等。
Could you tell me who knows the answer，please?
你能告訴我哪個了解答案嗎?
The small children don't know what is in their stockings.
這類孩子子不了解襪子里有哪些東西。
2)連接詞+名詞+謂語。連接詞在從句中作主語的定語。容易見到的連接詞有: whose, what, which, how many, how much等。
He asked whose handwriting was the best in our class.
他問大家班上哪個的書法最好。
The teacher asked us how many people there were in the room.
老師問大家房間里有多少人。
3)連接詞+主語+謂語。連接詞在從句中作賓語、狀語或表語。容易見到的連接詞有: who, what, which, how many, how much, when, why, how, where, if/whether等。
He hasn't decided if he'll go on a trip to Wuxi.
他還沒有決定是不是去無錫旅游。
Could you tell me what I should do with the money?
你能告訴我我怎么樣處置這筆錢嗎?
4)連接詞+名詞+主語+謂語。連接詞在從句中作賓語或表語的定語。容易見到的連接詞有: what, which, how many, how much, how等。
Do you know which class he is in?
你了解他在什么班嗎?
She asked me if I knew whose pen it was.
她問我是不是了解這是哪個的鋼筆。
引導詞
1)that
當由陳述句充當賓語從句時，用that引導，that無詞義，不充當句子成分，在口語或非正式文體中常省略。
I expect the plane would be diverted.
2)if/whether
當由一般疑問句充當賓語從句時，用if或whether引導，意為“是不是”，不充當句子成分，但不可以省略。
I don't know if/whether he still lives here after so many years.
3)特殊疑問詞
假如賓語從句原來是特殊疑問句，僅需用原來的特殊疑問詞引導
疑問代詞：what, which, who, whom, whose, whatever...
有詞義，充當句子成分
We'll do whatever we can to save him.
疑問副詞：where, when, how, why...
有詞義，充當句子成分
He knows where they live.
Tell us how you are getting on now.
以上三類總結起來就是：
that: 不充當成分，無意義，可以省略;
If/whether: 不充當成分，有意義，不可省略;
疑問代詞/副詞: 充當成分，有意義，不可省略。
記憶口訣：
陳述句用that，
一般疑問句if或whether，
特殊問句用疑問詞。
九種賓語從句不省略that
1)放句首表強調
That he is a good person, we all know.
2)主句的謂語動詞與賓語從句之間有插入語
Just then I noticed, for the first time, that he prepared to talk to us.
3)有間接賓語時
Lucy told me that she would not come to school tomorrow.
4)當 it 作形式賓語時
We have made it clear that we will learn to deal with various difficult problems.
5)介詞besides、beyond、but、except、in、save 后的賓語從句
The man stood quite still, except that his lips moved slightly.
6)主句中的動詞后有 2 個或以上的賓語從句，第二個及未來的 that 不可省
I think it will clear up this afternoon and that they will come to the party.
7)賓語從句本身是一個復合句
He said that if he came back early, he could come for the meeting.
8)當 that 從句單獨用來回答問題時
-What did he say at the meeting?
-That the situation was serious.
9)在較為正式或不常見的動詞后，如reply, object
He replied that he badly mastered the language.
☆注：以上9種狀況考察頻率依次遞減
if和whether有什么區別
if和whether都可譯為"是不是"，在從句中不作句子成分，二者引導賓語從句時一般可以互相替換，口語中多用if代替whether。
1)只可以用whether，不可以用if 引導的賓語從句
①當賓語從句中，緊接or not 時，只用whether ,不然都可。
Let me know whether/if you can come or not.
②當賓語從句提到句首時，只可以用whether ,不可以用if。
Whether it is true, I can't tell.
③whether 可以引導帶to 的不定式，而if不可以。
I don't know whether to accept.
④whether 可以放在介詞后，做介詞的賓語，而if不能。
I worry about whether I hurt her feelings.
⑤若if有歧義，只可以用whether。
Please let me know whether you want to go.
⑥動詞discuss, decide, consider, sure等后習慣上也常用Whether引導從句，不需要if。
Time for her to decide whether she wants to continue the journey.
⑦引導主語從句和表語從句時宜用whether。
Whether she will come or not is still a question.
她是不是能來還是個問題。
The question is whether we can catch the bus.
問題是大家能否趕上公共汽車。
2)只可以用if，不可以用whether 引導的賓語從句
①if引導條件狀語從句，意為“假如”
The students will go on a picnic if it is sunny.
②if引導否定定義的賓語從句時
He asked if I didn't come to school yesterday.
③引導狀語從句even if和as if時
He talks as if he has known all about it.
總結：
只可以用whether，不可以用if
①當賓語從句中，強調任意選擇出現or或緊接or not 時，只用whether，不需要if;
②當賓語從句提到句首時，只可以用whether，不可以用if;
③whether 可以引導帶to 的不定式，而if不可以;
④whether 可以放在介詞后，做介詞的賓語，而if不能;
⑤若if有歧義，只可以用whether。
⑥動詞discuss, decide, consider, sure等后習慣上也常用Whether引導從句，不需要if。
⑦引導主語從句和表語從句時宜用whether。
只可以用if，不可以用whether
①if引導條件狀語從句，意為“假如”;
②if引導否定定義的賓語從句時;
③引導狀語從句even if和as if時。
時態
1)主現從不限。
賓語從句中，假如主句是目前時態，從句的時態依據實質狀況來定，不受主句限制。
I know she lives here.
I know she lived here ten years ago.
2)主過從必過。
賓語從句中，假如主句是過去時態，那樣從句的時態肯定也是用過去的時態。
She told me that she was 15 last year.
3)客觀真理永一現。
假如賓語從句講述的是某種客觀真理，這時，需要用一般目前時。
She told her daughter that the earth is round.
否定轉移
1)什么叫賓語從句的否定轉移?
就是賓語從句表示否定時，將否定詞 not 轉移到主句中
舉例：“我覺得他不會來” 該如何說呢?
你或許會說：- I think he will not come.
但更地道的表述是：- I don't think he will come.
就是那種我不否定你，我只否定我一個人的感覺。
2)什么時間進行否定轉移呢?
進行否定轉移一般要滿足三個條件：
①主句的主語是第一人稱 I 和 we
②主句的謂語動詞是表示“覺得”、“相信”、“期望” 等主觀想法的詞
容易見到：think、believe、suppose、expect、imagine、feel
③主句時態為一般目前時
I don't believe that they can accomplish the task in such a short time.
We don't imagine that they will join the competition.
賓語從句后置
1)什么是賓語從句后置?
就是用一個“it”來代替整個賓語，然后將賓語從句的地方移到句末。
2)那種情況下會出現賓語從句后置?
①“喜、怒、哀、樂”
appreciate, enjoy, like, dislike, love, hate, prefer...
We would appreciate it if you could set up our payment arrangement.
假如你能安排付款，大家會很感激。
②“覺得、發現”
think, make, find, consider, feel, suppose...
He hasn't made it known when he is going to get married.
他還沒有宣布他何時結婚。
I consider it wrong to cheat in an examination.
我覺得考試作弊是不對的。
③介詞后
answer for, depend on, rely on, insist on, look to, see to, stick to...
You can depend on it that he will finish the job on time.
你可以相信他會按時完成這項工作。
簡化賓語從句常用六法
常會遇見把含有賓語從句的復合句轉化為簡單句，使其與原句意思相同的考試試題。下面就介紹幾種常見的簡化賓語從句的辦法：
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。
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。
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，且后帶雙賓語，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。
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，require等時，假如主句和從句的主語不同，賓語從句可簡化為“名詞+不定式”結構。
The headmaster ordered that we should start at once. → The headmaster ordered us to start at once.
4)某些動詞后的賓語從句，可以用介詞加動名詞等其他形式簡化。
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)某些動詞后面的賓語從句可轉化為“賓語+V-ing形式”結構。
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后的賓語從句，也可以用不定式來簡化，但句型需要進行適合的變化。
It seemed that the boys were going to win. →The boys seemed to win.
除上述辦法外，還有一些特殊句式的轉化。
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.
賓語從句和狀語從句的區別
eg. 1) I will go out tomorrow if it is fine.
2) I don’t know if the train has arrived.
句1中if引導的是狀語從句。這個從句表示“條件”，修飾主句。整個句子的意思是：假如明每天氣好，我就出去。句2中if引導的是賓語從句，充當謂語動詞don't know的賓語。整個句子的意思是：我不了解火車是不是到達。
判斷辦法：
1)可以從整個句式看。狀語從句一般可以放在主句的前面或后面，賓語從句只能放在主句謂語動詞之后。
2)從引導詞看。if充當賓語從句的連接詞時，等于whether， 詞義為“是不是”，充當狀語從句的連接詞時，詞義為“假如”。when充當賓語從句的連接詞時，意為“什么時間”，充當狀語從句的連接詞時，意為“當……的時候”。
2)從時態看。if和when作連接詞時，引導賓語從句應該注意：從句的謂語動詞的時態應依據主句的時態作相應的變化。if和when充當從屬連詞時，引導條件和時間狀語從句，若主句的謂語動詞用一般以后時，則從句的時態應用一般目前時表示以后。
—Do you know when he will come back tomorrow ?你了解他明天什么時間回來嗎?
—Sorry, I don't know.When he comes back，I'll tell you.對不起，不了解。當他回來了，我將對你說。
—I don't know if he will come.我不了解他會不會來。
—He will come if it doesn't rain.假如不下雨，他會來的。
其他需要說明的問題
1)標點由主句決定，如主句是陳述句、祈使句，則用句號;是疑問句則用問號。
I heard she had been to the Great Wall.
Can you tell me which bus I should take?
2)應該注意個別句子中主從句人稱的一致。
3)賓語從句的附加疑問句。
賓語從句的復合句在變成反意疑問句時，假如主句的謂語動詞為 think, guess, believe, suppose 等且主語為第一人稱時，附加部分要由從句決定;假如主句不是 think 等上述動詞或謂語動詞是這類詞且主語不是第一人稱時，附加部分由主句決定。
I think that he is right, isn't he?
I don't believe he is a student, is he?
He supposes that she will come tonight, doesn't he?
He never said he was a good student, did he?
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