考察的三个要点：语序，时态，关联词。

1.定义：用作宾语的从句叫宾语从句。

2.构成：关联词+简单句。

3宾语从句的语序一定是陈述句语序。（who 作主语的从句本身就是陈述句语序）

4宾语从句在复合句中作主句的宾语，连接宾语从句的连词有that（that在口语中常省略）。 whether，if，和连接代词what， which， who， whom及连接副词when， where， how， why。

He knew（that） he should study hard.

他知道他应该努力学习。

Can you tell me which class you are in？

您能告诉我，您在哪一班吗？

He asked me if he could come in，

他问我他是否能进来。

5.引导宾语从句的关联词有三类：

（1）从属连词that.如：一般那情况下可以省略。

He told us that he felt ill.

I know he has returned.

注： that在引导宾语从句时也并不是任何情况下都可以省略。在以下情况下，that不能省略。

1.Everybody could see what happened and that Tom was frightened.

（and连接两个宾语从句，that宾语从句放在and的后面时，that不能省略。）

2.I know nothing about him except that he is from the south.

（that引导的宾语从句作介词宾语时，that不能省略。）

3.That he ever said such a thing I simply don’t believe.（that从句位于句首时，that不可省略。）

我简直不相信他曾说过这样的话。

（2）从属连词if/whether.如：

I doubt whether he will succeed.

I don’t know if you can help me.

（3）连接代词who，whom，whose，what，which，whoever，whatever，

whichever

连接副词 where，when，how，why.

Who or what he was，Martin never learned.

I wonder what he’s writing to me about.

I’ll tell you why I asked you to come.