宾语从句在复合句中做主句的宾语，是初中英语教学大纲规定掌握的二种复合句之一，是非常重要的语法项目 ，学习时应从下面几个方面去系统掌握：
一.连词
1.宾语从句具有陈述意义时用that引导，在口语或非正式文体中常省略。如：He said (that)he had been to Beijing.他说他去过北京。
I'm sure(that)she won't mind. 我肯定她不会介意的。
2.宾语从句具有一般疑问意义时用连词if 或whether引导，口语中常用if。如：She asked me if(whether) she could come in. 她问我她是否能进来。
He asked if you had white hat.他问你是否戴着白色的帽子。
注意：if和whether在用法上是有区别的。(1)if可以引导条件状语从句，whether不能。如：I 'm coming here if it doesn't rain tomorrow.(如果明天不下雨我就来这里。) (2)在下列情况时只能用whether：用作介词的宾语时；用在不定式前面时；whether引导的从句置于句首时。如：
It depends on whether I have enough time. 这得由我是否有足够的时间来决定。
He doesn't know whether to go or not.他不知道要不要去。
Whether this is true or not,I can't say.这是不是真的，我说不准。
(3)whether和if常与or not连用，whether和or not 既可合起来使用，也可分开使用；if和or not只能分开使用。如：
He asked whether(if)they would come or not.他问他们是否该来。
I don't know whether or not they will come.我不知道他们来不来。
(4)whether 引导的宾语从句一般是肯定句，if 引导的宾语从句可以是肯定也可以否定的。如:
She asked whether/if you had enough money.她问你是否有足够的钱。
I don't care if it doesn't rain.我不在乎是否下雨。（只能用if)
3.宾语从句具有特殊疑问含义时用连接代词（what,who,which,whose)或连接副词（when,where,why,how)以及有how构成的词组how many,how long等。如： The children didn't know who Father Christmas was.孩子们不知道圣诞老人是谁。Do you know when they'll leave？你知道他们什么时候离开？
值得注意的是，宾语从句与主句之间需要有连词进行连接，除that可以省略外，其它连接词是不能省略的，更不能重复使用。如：“请告诉我们老师讲得什么。”不可以译为：Please tell us that what the teacher said.
二.语序
宾语从句有时是疑问句的意思但语序必须是陈述句语序。特别是由助动词构成的疑问句做宾语从句时。如：
我想知道他在做什么。[误]I want to know what is he doing.
[正]I want to know what he is doing.
告诉我他什么时候离开的。[误]Tell me when did he leave.
[正]Tell me when he left.
三.时态
宾语从句与主句应在时态上保持一致。如果主句是一般现在时，宾语从句可根据实际情况选择适当的时态；如果主句是过去时，从句必须也是过去时的某种时态（一般过去时，过去进行时，过去完成时，过去将来时等）。但当宾语从句叙述的是一普通真理或客观规律时，则用一般现在时。如：
I know he lives here.我知道他住在这里。
I knew who lived here.我知道谁住过这儿。
He said that the sun rises in the east.他说太阳从东方升起。
四.否定转移
主句为I think/believe/guess等时，其后面宾语从句的否定应转移到主句上，且附加问句要按从句确定。有否定转移时，要将否定移回到从句上再决定附加问句的形式。如：I don't think he'll be back,will he?
I think he can answer the question,can't he?
五.宾语从句的简化
宾语从句在一定条件下可以转换成简单句，一般有下列几种方法：
1.用动词不定式代替宾语从句。如:
She hopes that she will be back soon.→She hopes to be back soon.
He agreed that he would help me with my English.→
He agreed to help me with my English.
2.用“疑问词+不定式”结构代替宾语从句。如：
I don't know what I should do next.→I don't know what to do next.
Please tell me how I can finish the work on time.→
Please tell me how to finish the work on time.
3.用复合宾语,即宾语加宾语补足语代替宾语从句。如：
I saw that he went into the house just now.→
I saw him go into the house just now.
Can't you see that the boy is climbing the tree?→
Can't you see the boy climbing the tree?
I heard she was singing in English.→I heard her singing in English.
Tom's mother found he was a very good pupil.→
Tom's mother found him a very good pupil.
4.用名词或名词短语代替宾语从句。如：
Do you understand what I said? →Do you understand my words?
Could you tell me where the hospital is?→
Could you tell me the way to the hospital? 定语从句注意要点
1，只能用that,不能用which,who 的几种情况
1）先行词是人又是物：
The person and his dog that were killed in the accident were bury.
The man and his school ____you told me are very interesting.
2)先行词是不定代词：anything,something,everything,nothing,all,the one 等词
(1)Has everything that can be done been done?
(2)All that you told me was difficult to understand.
3)先行词被最高级修饰
（1)It is the longest film that I have seen all in my life.
4)先行词被序数词修饰
(1)It's the first time that I've been to Beijing.
（2)The first stamp that was invented appeared in England
5)先行词被just ,very,only等强调词语的修饰。
（1）It's the very house that I want to buy.
(2)Only the vegatable that hasn't been polluted is save to eat.
2.只能用which ,who不能用that的两情况：
1）非限制性定语从句
Changjiang,which is the third longest river,lies in China.
Do you know Chairman Mao,who used to be the chairman of the Party?
2)整句话当先行词：
It rained a lot,which made a flood happened.
He tore my photo,which made me angry.
3.只能用as，不能用which,that,who的两种情况：
1）先行词被such,the same 修饰
I've never heard of such a terrible earthquake _____ you told me.
对比：It's such a terrible earthquake ______many people were killed.
定语从句的动词和先行词有动宾关系，结果状语从句反之。
2）整句话当先行词，且从句有“正如.......所知道/预料的一样”
Taiwuang belongs to China,as we know.
As everybody can see, we have a good harvest in fruit this year,the fruit will be cheap.
对比which 修饰整句话当先行词：
1。which引导的句子有“这就使...”造成什么客观后果的意思，而as 引导的句子都是主观认识的动词：如know，see,expect,was told 之类。
2。as 引导的定语从句可放句首，（这是唯一能放在先行词前的定语从句。当然，它也可放先行词后。而which 肯定要放先行词后。3。先行词和which 之间肯定有逗号隔开，而"the same .....as......""such ......as......"没有逗号隔开。整句话当先行词，主从句之间都必须有逗号隔开。
4.只有that,which 在当定语从句中的宾语时可省略，其它情况下的关系代词都不能省略。
5.只能用when,where,不能用that,which的情况：关系代词在从句中当状语。例如当live,work,study等不及物动词的状语，而当从句动词是visit,spend,build,buy等及物动词时就应用that,which。状语从句学习要点：
* I. 时间状语从句
*
* 1.while, as, when 做引导词
* while只能表持续性的动作或状态，不能表一时性或短暂性的动作，主句和从句的动作同时发生，且持续时间长。
* as也可表持续性动作，但持续时间较短，主句、从句动作也是同时发生。
* when既可表一时性动作，也可表持续性动作。可指一个时间段，也可指一个时间点，从句的动作可和主句的动作同时发生，也可先于主句的动作发生。
* While the teacher explained the text, the students listened attentively and took notes.
* She entered the room when the meeting was going on.
* The earth turns round its axis as it travels round the sun.
*
* 2. till, until做引导词
* 两词可通用，都表主句谓语动词的动作持续到从句谓语动词的动作发生时为止,until引导的从句可放句首，till引导的一般放句末。主句有否定含义时，until, till都有before之意，not until放在句首主谓要倒装。
* She stood there till/until he had passed out of sight.
* He did not stop to rest until he had finished the work.
* Not until Mary had heard that sound was she really frightened.
*
* 3. as soon as, the moment, the minute, the instant, directly, once, immediately引导的时间状语从句都表示从句的动作一发生，主句的动作随即发生，且主句和从句的时态相同，通常译成"一......就......"
* no sooner... than, hardly/scarcely...when表主句、从句动作相继发生，一般主句用过去完成时，从句用过去时。如果hardly, no sooner, scarcely提前，主谓要倒装。
* As soon as he saw me, he ran away.
* They told me the news immediately they got the message.
* Hardly had he gone to bed when the door bell rang.
* 4. 时间状语从句不用将来时，一般现在时表将来，一般过去时表过去将来。
* II. 地点状语从句
* 用where或wherever引导
* You can see flowers in spring wherever you go.
* III. 条件状语从句
* 1. 条件状语从句用一般现在时表将来。
* 2. Unless, if, if only引导的状语从句
* unless表反面的条件，=if...not，"除非"
* if表正面条件，"如果"
* if only表强烈愿望或遗憾，用虚拟，"但愿..."
* If you work hard at your lessons, you are bound to pass the examination.
* You will miss the bus unless you walk more quickly.
* If only I had more money, I could buy some new clothes.
* 3. 由provided (that), providing (that), supposing (that), suppose (that), as long as, so long as, on condition that, in case等引导，与if 相近，常有"如果"、"只要"、"假如"、"假使"、"在...条件下"等。
* Supposing you fell in love with your boss, what would you do?
* You are welcome to stay with us as long as you share the rent.
* In case Mary comes, please tell her to come to my office.
* I will give you the day off on condition that you work on Saturday morning.
*
* IV. 原因状语从句
* 1. as, because, since, for
* as: 表示原因的语气比because要弱，一般放在句首；
* because的语气最强，对已明确的事实表示稍加分析后的原因，一般放句末，也可放句首；
* since一般放句首；
* for一般表补充解释，一般放句末。
* The engine stopped because the fuel was used up.
* As a steel ship is hollow, it floats on water.
* Since no one is against it, we will adopt the proposal.
* 2. Seeing (that), considering (that), now that "鉴于"， "由于......"
* Seeing that I shall be here again tomorrow, I won't wait any longer.
* Now that everybody is here, let's begin our meeting.
* Considering that he has only been learning English for a year he speaks it very well.
*
* Ｖ. 目的状语从句
* １、so that, that, in order that
* 主句如用一般现在时，从句用情态动词may/can; 若为一般过去时，则用could/should或might. In order that可放主句前或后，so that 只能放主句后。
* ２、lest, for fear that, in case有"以防"、"以免"之意，lest后一般用should+动词原形，in case一般用虚拟语气，有时也用陈述句。
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