在句中担当宾语的从句叫宾语从句，宾语从句可作谓语动词的宾语，也可做介词的宾语。
eg：He said he was good at drawing. (动词宾语)
He asks him how long Mike has been down . (动词宾语)
Miss Zhang is angry at what you said. (介词宾语)
宾语从句的引导词有三类：
(1)以that 引导的宾语从句，主要用来引导句形式的宾语从句， that可以省略。
eg：The radio says (that) the clouds will lift later on.
She told me (that) she would like to go with us.
(2)以连接代词which, what, who等或连接副词how, where, why 等引导的宾语从句，从句是陈述语序
eg：Could you tell me what’s the matter with u?
I want to know how soon it will begin.
(3)以 whether 或 if 引导的宾语从句, 主要用来引导一般疑问句意思或选择疑问句意思的宾语从句，从句同样是陈述语序
eg：I wonder if /whether u have told the new to Li Lei .
宾语从句的时态
(1)当主句为一般现在时态、现在进行时态、或一般将来时态时，从句可用所需要的任何时态。
eg, I want to know what time he got up this morning.
You are telling me that you won’t stop until tomorrow?
(2)当主句为一般过去时态时， 从句要用于过去有关的时态。
eg：They asked what Jean was doing now .
Linda said that the train had left.
(3)当从句表述的是客观真理或自然现象时，宾语从句要使用一般现在时。
eg：Lisa asked whether light travels faster than sound.
Polly said no news is a good news
注意：一般情况下，whether 和if 可以互用， 但有些情况例外。
1.当从句做介词的宾于是只用whether 不用if
eg：We are talking about whether we’ll go on the pinic.
2.引导词与动词不定式或 not 连用时， 只用whether.
eg：Please let me know what to do next.
Could you tell me whether u go or not?
3. if当如果讲时，引导的是条件状语从句，这时不能用whether.
eg：You can’t work the plan out if you don’t have the meeting .
