一.賓語從句的定義
置于動詞、介詞等詞性后面起賓語作用的從句叫賓語從句。賓語從句的語序必須是陳述語序。謂語動詞、介詞、動詞不定式，v.-ing形式后面都能帶賓語從句。有些形容詞(afraid,sure,glad等)之后也可以帶賓語從句。
二.賓語從句中引導(dǎo)詞的用法
在復(fù)合句中作主句的賓語，引導(dǎo)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。(一)that引導(dǎo)的賓語從句(在非正式場合that可以省略)
可跟that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。
例句：The boy believes that he will travel through space to other planets.
注意事項：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(zhuǎn)移至主句表示。
例句：I don’t think it is right for him to treat you like that.
在以下情況中that不能省略
1當句中的動詞后接多于兩個由that引導(dǎo)的賓語從句時，第一個that可省，但后面的that不可省。
例句：He said (that) you were too young to understand the matter and that he was asked not to tell you.
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。
例句：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。
例句：I can’t tell him that his mother died.
注意事項：許多帶復(fù)合賓語的句子，that引導(dǎo)的賓語從句經(jīng)常移到句子后部，而用it作形式賓語。
例句：I find it necessary that we should do the homework on time.
(二)由whether,if 引導(dǎo)的賓語從句
由whether(if)引導(dǎo)的賓語從句，實際上是一般疑問句演變而來的。意思是"是否"。賓語從句要用陳述句語序。一般說來，在賓語從句中whether與if可以互換使用，但在特殊情況下if與whether是不能互換的。
例句：I wonder whether(if) they will come to our party.
只能用whether，不能用if引導(dǎo)的賓語從句
1在帶to的不定式前
例句：We decided whether to walk there.
1在介詞的后面 例句：I’m thinking of whether we should go to see the film.
2在動詞后面的賓語從句 例句：We discussed whether we had a sports meeting next week
3直接與or not連用時 例句：I can’t say whether or not thet can come on time.
只能用if不能用whether引導(dǎo)的賓語從句
1 if引導(dǎo)條件狀語從句，意為"如果" 例句：The students will go on a picnic if it is sunny.
2 if引導(dǎo)否定概念的賓語從句時 例句：He asked if I didn’t come to school yesterday.
3 引導(dǎo)狀語從句even if(即使)和as if(好象)時 例句：He talks as if he has known all about it.
(三)連接代詞和連接副詞引導(dǎo)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。用于這種結(jié)構(gòu)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。
英語中的連接代詞有：who,whom,whose,which,what,在句中擔任主語、賓語、定語或者表語。
例句：Can you tell me whom you are waiting for?
英語中的連接副詞有：when,where,why,how，在句中擔任狀語的成分。
例句：None of us knows where these new parts can be bought.
三.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。例句如下：1 I don’t know what they are looking for. 2 Could you tell me when the train will leave?
3 Can you imagine what kind of man he is?
四.賓語從句的時態(tài)
1主句是一般現(xiàn)在時，從句根據(jù)實際情況使用任何時態(tài)。例句：The headmaster hopes everything goes well.
2主句是過去時態(tài)，從句須用過去時態(tài)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(xiàn)在時態(tài)。
例句：The teacher told his class that light travels faster than sound.
五.賓語從句的特點
1賓語從句可以作及物動詞、介詞及形容詞的賓語。 2 賓語從句的語序一律用陳述句語序。
3連接詞that引導(dǎo)賓語從句在句中無詞義，不充當句子成份，多數(shù)情況下可以省略。
4whether 和 if 都可引導(dǎo)賓語從句，但 whether后可緊跟or not;whether從句可作介詞的賓語。
5 如果從句太長，可以用形式賓語it.
