时。如:

　　●The teacher told us that the moon moves around the earth.

　　用法注意

　　一、if和when既能引导宾语从句,又能引导状语从句。因此,一定要认清它们一种形式的“两副面孔”,从而准确地判断句子的类型。如:

　　I don’t know if / when he will come tomorrow. (宾语从句)

　　If / When he comes, I’ll tell you about it.(状语从句)

　　二、 宾语从句与简单句

　　含有宾语从句的复合句有时可以变为简单句。该知识点在句型转换的题型中经常会作为考点出现。现归纳如下:

　　1. 在某些由疑问词(why除外)引导的宾语从句的复合句中,当从句的主语与主句的主语一致时,原复合句可以变为简单句。

　　【变法】把宾语从句转换为“疑问词+动词不定式”结构作主句谓语动词的宾语。如:

　　I want to know how I can open the door.

　　→I want to know how to open the door.

　　2. 在某些由疑问词(why除外)引导的宾语从句的复合句中,当从句的主语与主句谓语动词的间接宾语一致时,原复合句可以变为简单句。

　　【变法】把宾语从句转换为“疑问词+动词不定式”结构作主句谓语动词的复合宾语。如:

　　Could you tell me how I can get to the post office?

　　→Could you tell me how to get to the post office?

　　3. 在某些由that引导的宾语从句的复合句中,当从句的主语与主句的主语不一致时,原复合句可以变为简单句。

　　【变法】原复合句可变为“主语+谓语+宾语+宾补”的句型。如:

　　We found that the boy was very clever.

　　→We found the boy very clever.

　　I saw that they were playing basketball there.