B,由连词if、 whether 引导的表示“是否…”的宾语从句。Whether,if 在从句中不做句子的成分，一般情况下，whether和if 可以替换。

例：I don’t know if/whether he will come tomorrow.

The teacher asked if/whether we had finished the experiment.

l在介词后面的宾语从句中不用if引导

例：Everything depends on whether we have enough money。

l宾语从句中有or not时不用if引导.

例：I don’t know whether the movie star will come or not.

l和不定式连用作宾语时不用if引导.

例：Whether to go there or not hasn’t been decided.

C,由wh-引导的宾语从句。连接代词who,whom,whose, what, which,和连接副词when, where, why, how 等连接的宾语从句，它们在句中即有连接从句的作用，又在句中充当句子的成分。

例：Do you know which film they are talking about? (which做定语)

I don’t know where he lives. (where 做地点状语)

二，宾语从句的语序，

宾语从句从句的语序必须是陈述语序，即连接词+主语+谓语+其他成分

例：I believe that they will come soon.

He asked me whether I was a teacher.

They wanted to know what they can do for us.

二，宾语从句的时态。

宾语从句的时态受主句的限制，

既：主句是一般现在时态，从句根据实际情况而定。

主句是一般过去时态，从句用相应的过去的时态。如果从句的动作发生在主句之前，则从句要用过去完成时态。

例:

1)She says that she is a student.

She said that she was a student.

2)She says that she will fly to Japan in a week.

She said that she would fly to Japan in a week.

3)She says that she has finished her homework already.

She said that she had finished her homework already.

4)She says that she can sing a song in English.

She said that she could sing a song in English.

l如果宾语从句说的是客观真理、自然现象或事实时，这时宾语从句要用一般现在时态。

例：The teacher said that the earth goes round the sun.

He told me that Japan is an island country.

lCould you tell me…是用来征询对方的意见，语气委婉，并不表示过去。

例：Could you tell me when we will visit the Histury Museum?

注意事项：

u由陈述句变成宾语从句时，要注意人称的变化。

例：She said: “I have been to England before.”

She said that she had been to England before.

She asked me: “Do you like maths?”

She asked me if I liked maths.

u宾语从句与简单句的交换。

由连接代词和连接副词引导的宾语从句，如果宾语从句的主语和主句的主语是同一个人时，可以用“疑问词+不定式

”做宾语的简单句结构。

例：I don’t know what I should do next.

I con’t know what to do next.

He didn’t know where he would live.

He didn’t know where to live.

以上为大家分享的宾语从句的相关内容，精品学习网希望同学们可以认真理解并掌握。

相关链接：

2016高中英语语法限定性定语从句解析 

2016高中英语语法分隔式定语从句例析