宾语从句：在句子中起宾语作用的从句。
I like it.
(i是主语；like 是谓语；it是宾语)
I like what I do.
(I是主语；like是谓语；我喜欢构成了主谓，我喜欢宾语，宾语就是what I do，what I do 为起宾语作用的从句)
分为动词宾语、介词宾语、形容词宾语。
动词宾语：I think 【that we have to delay the meeting.】介词宾语：The result is all depends on【 how hard you work.】形容词宾语：I am not sure 【that you can learn English well. 】
从属连词that引导；是否whether/if引导；疑问意义连接词who/which/what等引导。
That引导宾语从句，谓语动词通常是：think,hope,say,tell,know,see,hear,mean,feel,wish等。I hope that I can make the world peace.
I mean that the situation is urgent.
That 引导系表结构宾语从句，大多为描述心理活动、感觉的词语：afraid,sorry,sure,glad,happy,angry,worried等。I am afraid that smoking is not allowed here.
I am sure that you can pass the exam.
是否whether/if引导宾语从句。I am not interested in whether she will come or not.
Do you know if there are any nice restaurants around here?
连接代词引导宾语从句。Do you know what he said?
Could you tell me which gate we have to go to?
连接副词引导宾语从句。I want to know how it works.
He explained why he should go back.
1. 句子中有并列连词引导的两个或两个以上的that引导的宾语从句，仅第一个从句的that可以省略，其余that必须保留。
she said that she would come and that she would help me.
She said she would come and that she would help me.
2. That引导的宾语从句中又有从句,that不可以省。
I am afraid that if you’ve lost it,you must pay for it.(that引导宾语从句，if引导条件从句)
3. It 做形式宾语，that 引导从句，that不可以省略。
We have made it clear that we will deal with it.(第一个it是形式宾语)
4. Whether…or not，与or not搭配仅能用whether,不能用If。
I don’t know whether he can come or not.
5. 遇到不定时连词只能用whether不能用If。
I couldn’t decide whether to do it.
6. 前面的词语是介词用whether不能用If。
There has been now news about whether they have finished their work.
