宾语从句是初中英语知识中的重点和难点，下面为大家详细讲解一下。
一、概述
宾语从句是主从复合句的一种。主从复合句是由一个主句和一个或一个以上的从句构成的。
主句是复合句的主体，从句仅仅是主句的一个成分，它从属于主句，不能独立。从句在全句中充当什么成分，就叫什么从句。宾语从句当中的从句在全句中作宾语。
简单句She knew the teacher(宾语)复合句She knew that the teacher hadseen the film.(宾从)
二、宾语从句
1.语序
无论主句是陈述句还是疑问句，宾语从句都必须使用陈述语序，即“主句+连词+宾语从句(主语+谓语+……)”句式。根据连接词在从句中所担任的不同成分，可分为以下四种：
1)连接词+谓语。连接词在从句中作主语。常见的连接词有：who，what，which等。如：
Could you tell me who knows theanswer，please?你能告诉我谁知道答案吗?
The small children don't knowwhat is in their stockings.这些小孩子不知道袜子里有什么东西.
I don't know which belongs tomy father.
2)连接词+名词+谓语。连接词在从句中作主语的定语。常见的连接词有：whose，what，which，how many，how much等。如：
He asked whose handwriting wasthe best in our class.他问我们班上谁的书法最好。
The teacher asked us how manypeople there were in the room.老师问我们房间里有多少人。
3)连接词+主语+谓语。连接词在从句中作宾语、状语或表语。常见的连接词有：who(m)，what，which, how many, how much,when, why, how, where, if /whether(在句中不充当任何成分)。如：
He hasn't decided if he'll goon a trip to Wuxi.他还没决定是否去无锡旅行。
Could you tell me what I shoulddo with the money ?你能告诉我我如何处理这笔钱吗?
4)连接词+名词+主语+谓语。连接词在从句中作宾语或表语的定语。常见的连接词有：what，which，how many，how much，how等。如：
Do you know which class he isin ?你知道他在哪个班吗?
She asked me if I knew whosepen it was.她问我是否知道这是谁的钢笔。
2.连接词
1)当由陈述句充当宾语从句时，用that引导，that无词义，在口语或非正式文体中常省略。如：
He said that he could finishhis work before supper.他说他会在晚饭前完成工作。
2)当由一般疑问句充当宾语从句时，用if或whether引导，意为“是否”。如：
I don't know if /whether hestill lives here after so many years.
但在下列情况下只能用whether：
①在具有选择意义，又有or或or not时，尤其是直接与or not连用时，往往用whether(if…or not也可以使用)。如：
Let me know whether /if he willcome or not.(=Let me know whethe or not he will come)
I don't know whether/if he doesany washing or not.(=I don't know whether or not he does any washing.)
I wonder whether we stay orwhether we go.
②在介词之后用whether。如：
I'm interested in whether helikes English.我关心的是他是否喜欢英语。
We're thinking about whether wecan finish the work on time.
I worry about whether I hurther feelings.我担心是否伤了她的感情。
③在不定式前用whether。如：
He hasn't decided whether tovisit the old man.他尚未决定是否拜访那位老人。
I don't know whether to go.我不知去否。
He hasn't decided whether to goby bus or by train.他还未决定是乘公共汽车去还是坐火车去。
④whether置于句首时，不能换用if。如：
Whether this is true or not，I can't say.这是否真的我说不上来。
⑤引导主语从句和表语从句时宜用whether。如：
Whether she will come or not isstill a question.她是否能来还是个问题。
The question is whether we cancatch the bus.问题是我们能否赶上公共汽车。
⑥若用if会引起歧义时，则用whether。如：
Please let me know if you likethe book.可理解为：a. Please let me know whether you like the book.请告诉我你是否喜欢这本书。B. If you like the book, pleaselet me know.你如果喜欢这本书，请告诉我。
3)如果宾语从句原来是特殊疑问句，只需用原来的特殊疑问词引导。如：
Could you tell me why you werelate for the meeting this morning?
3.时态
含宾语从句的复合句，主、从句谓语动词的时态呼应应包括以下三点内容：
1)如果主句的谓语动词是一般现在时，从句的谓语动词可根据需要，选用相应的任何时态。如：
I don't know when he will comeback.我不知道他将何时回来。
He tells me that his sistercame back yesterday.他告诉我他姐姐昨天回来了。
2)如果主句的谓语动词是过去时，宾语从句的谓语动词只可根据需要，选用过去时态即一般过去时、过去进行时、过去将来时或过去完成时的某一种形式。如：
①The children didn't know who hewas.孩子们不知道他是谁。
②He asked his father how ithappened.他问他父亲这件事是如何发生的。
3)如果宾语从句所表示的是客观事实、普遍真理、自然现象或习惯性动作等，不管主句用什么时态，从句时态都用一般现在时。如：
The teacher said that the earthgoes round the sun.老师说地球绕着太阳转。
4.注意：
if和when既可以引导宾语从句，也可以引导状语从句，应注意它们在两种从句中的意思和用法的不同。if和when引导宾语从句时，分别意为“是否”和“何时”，其时态应和主句时态相呼应;它们引导状语从句时，意思分别为“如果，假如”和“当……时候”，当主句时态是一般将来时时，其时态用一般现在时。它们常常放在含有状语从句和宾语从句的题干中进行综合考查。如：
—Do you know when he will comeback tomorrow ?你知道他明天什么时候回来吗?
—Sorry, I don't know. When hecomes back, I'll tell you. 对不起，不知道。当他回来了，我将告诉你。
—I don't know if he will come.我不知道他是否会来。
—He will come if it doesn'train.如果不下雨，他会来的。
★宾语从句的复合句转化为简单句(六种方法)，使其与原句意思相同(或相近)的试题。
方法一：当主句谓语动词是hope，decide，wish，choose，agree，promise(和主观决定有关)等，且宾语从句的主语与主句主语一致时，宾语从句可简化为不定式结构。例如：
Li Ming hopes he will be backvery soon. →Li Ming hopes to be back very soon.
We decided that we would helphim. →We decided to help him.
方法二：当主句谓语动词是know，learn，remember，forget，tell(和记忆认知有关)等动词，且主句主语与从句主语一致时，宾语从句可简化为“疑问词+不定式”结构。例如：
She has forgotten how she canopen the window. →She has forgotten how to open the window.
注：当主句谓语动词是tell，ask，show，teach等动词，且后带双宾语，从句主语和间接宾语一致时，宾语从句可简化为“疑问词+不定式”结构。例如：
Could you tell me how I can getto the station? →Could you tell me how to get to the station?
方法三：当主句的谓语动词是order(命令)，require(需要)等时，如果主句和从句的主语不一致，宾语从句可简化为“名词(代词)+不定式”结构。例如：The headmaster ordered that weshould start at once. → The headmaster ordered us to start at once.
方法四：某些动词后的宾语从句，可以用介词加动名词(短语)等其他形式简化。例如：
He insisted that he should gowith us. →He insisted on going with us.
The poor boy doesn’t know whenand where he was born. →The poor boy doesn’t know the time and the place of hisbirth.
方法五：某些动词后面的宾语从句可转化为“宾语+V-ing形式(作宾语补足语)”结构。例如：Liu Ping found that there was awallet lying on the ground. → Liu Ping found a wallet lying on the ground.
方法六：动词seem后的宾语从句，也可以用不定式(短语)来简化，但句型需要进行适当的变化。例如：It seemed that the boys weregoing to win. →The boys seemed to win.
除上述方法外，还有一些特殊句式的转化。例如：
I found that it was difficultto learn English well. →I found it difficult to learn English well.
Soon we found that the groundwas covered with thick snow. →Soon we found the ground covered with thick snow.
They found that the box wasvery heavy. →They found the box very heavy