1. 从句的主语如果是第一人称，变为宾语从句则与主句的主语一致;如果是第二人称，则与主句的宾语一致;如果是第三人称，不用变化。如：

“May I use your knife?”He asked me. →He asked me if he might use my knife.

“Do you know her telephone number?”He asked me. →He asked me if I know her telephone number.

2. 宾语从句的标点均由主句决定。主句是陈述句，用句号;主句是疑问句，用问号。如：

Who will give us a talk?I don’t know. →I don’t know who will give us a talk.

Do you know?Where does he live?→Do you know where he lives?

四、两副面孔

if和when既能引导时间状语从句，又能引导宾语从句。因此，遇到它们就要认真分析一下，它们究竟属于“两副面孔”的哪一副。如：

If it rains tomorrow，I won’t come.(时间状语从句)

I don’t know if it will rain tomorrow. (宾语从句)

五、从句的简化

1. 当主句谓语动词是find，see，watch，hear等感官动词时，从句常简化为“宾语+宾补”结构，宾补为不带to的不定式或V-ing形式。如：

She found that the wallet lay/was lying on the ground. →She found the wallet lie/lying on the ground.

2. 当主句谓语动词是hope，wish，decide，forget，plan，agree等，且主句主语与从句主语相同时，从句可简化为不定式结构。如：

She agreed that she could help me with my maths. →She agreed to help me with my maths.

3. 在连接代词/副词引导的宾语从句中，当从句主语与主句主语或间接宾语一致时，宾语从句可简化为“连接代词/副词+不定式”结构。如：

Can you tell me how I can get to the station?→Can you tell me how to get to the station?