宾语从句引导词及用法总结

　　⑴连接词：①连词that引导由陈述句变来的宾语从句。如：I know (that) he’s a teacher. ②连词if或whether引导一般疑问句、反意疑问句或选择疑问句变来的宾语从句。如：Could you tell me if/whether it snows in winter in Australia?③连接代、副词（即疑问词）引导由特殊疑问句变来的宾语从句。如：Please tell me how you go to school.
　　⑵语序：宾语从句要用陈述语序。如：Do you know where Tom lives?
　　⑶时态：①如果主句为一般现在时、一般将来时，则宾语从句中时态不限，根据实际情况使用所需要的时态。如：I hear Joan left for Beijing yesterday. I hear Joan has left for Beijing. I hear Joan will leave for Beijing. ②如果主句为一般过去时，则宾语从句应与主句中的时态保持一致，只用过去时态的适当形式。如：Kate said she was watching TV this time yesterday. Kate said she was going to school soon. Kate said she had seen the film before. ③如果宾语从句表示的是客观真理和普遍事实，则一般现在时保持不变。如：Miss Hu said that the earth goes around the sun. ④如果宾语从句是when疑问句或带有时间状语从句，则when疑问句或时间状语从句中的一般过去时不变。如：The teacher wanted to know when the girl was born. Tom said he had worked here since he left school. ⑤如果宾语从句中含有过去具体的年、月、日作状语，则其一般过去时保持不变。如：I heard Lucy was born in 1986.
　　⑷否定前移：如果主句的谓语动词是think, guess, believe等表示猜测的动词且接有否定的that宾语从句，常将否定词提前到主句中。如：I don’t think that Alice is English.（我认为艾丽斯不是英国人。）
⑸复合结构：在think, find, make等接有复合宾语的动词之后，为避免句子头重脚轻或关系模糊，常用it作形式宾语，而将真正的宾语从句放在宾语补足语之后，即用“及物动词+it+宾语补足语+宾语从句.”结构。如：I think it important that we should learn English well.

 
宾语从句用法归纳
 1. 宾语从句概说
宾语从句即指在主从复合句中用作宾语的从句。宾语从句通常由连词that和whether (if)以及连接代词或连接副词引导。宾语从句的词序要用陈述句词序，不能用疑问句词序：
我不知道他想要什么。
误：I don't know what does he want.
正：I don't know what he wants.
2. 宾语从句的引导词
(1) 用that引导。that只起引导词作用，不充当句子成分，也没有词义，且通常可以省略：
We think (that) he will help us. 我们认为他会帮助我们。
He said (that) he was good at English. 他说他擅长英语。
I know (that) he is very busy. 我知道他很忙。
(2) 用if或whether引导。if和whether引导宾语从句，不充当句子成分，但有词义，表示“是否”：
I don't know if [whether] he will come. 我不知道他是否会来。
She asked if [whether] that was enough. 她问那是否够了。
I wonder whether [if] it is true. 我不知道是不是真的。
(3) 用连接代词引导。常见的引导宾语从句的连接代词有what, who, whom, which, whose等。此时要特别注意宾语从句用陈述句词序，而不用疑问句词序：
Ask him which he wants. 问他要哪一个。
She asked who would like to go. 她问谁愿意去。
Tell me whose wallet this is. 告诉我这是谁的钱包
【注】what引导宾语从句时，有时表示“什么”，有时表示“…所…的”。比较：
I asked what he needed. 你问他需要什么。
I gave him what he needed. 我给了他所需要的东西。
(4) 用连接副词引导。常见的引导宾语从句的连接副词有when, how, where, why等。此时要特别注意宾语从句用陈述句词序，而不用疑问句词序：
He knows where they live. 他知道他们住哪里。
Tell us how you are getting on now. 告诉我们你现在过得怎样？
I can't tell you why she is crying. 我不能告诉你她为什么哭。
He didn't say when he would return. 他没有说什么时候回来。
3. 宾语从句与形式宾语it
当宾语从句后跟有宾语补足语时，通常在宾语从句处使用形式宾语it，而将真正的宾语从句移至句末：
I think it best that you should stay here. 我认为你最好住这儿。
He hasn't made it known when he is going to get married. 他还没宣布他何时结婚。
4. 宾语从句与否定转移
当动词think, believe, suppose, expect, imagine 后接一个表示否定意义的宾语从句时，其否定通常转移到主语：
I don't think that he will leave. 我认为他不会离开。
I don't believe that it is easy. 我相信这不会容易。