由that, which, who和whom引导的`定语从句：
1.关系代词that引导的定语从句。that在从句中作主语或宾语，可以指人，也可以指物。
如：A plane is a machinethatcan fly. (作主语，指物)
That’s is the best hotelthatI know. (作宾语，指物)
Who is the manthatis reading a book over there? (作主语，指人)
The girlthatwe saw yesterday is Jim’s sister. (作宾语，指人)
2.关系代词which引导的定语从句。which在从句中作主语或宾语，只可以指物。
如：They planted some treeswhichdidn’t need much water. (作主语，指物)
The fishwhichwe bought this morning were not fresh. (作宾语，指物)
3.关系代词who和whom引导的定语从句。who和whom只可以指人，分别在从句中作主语或宾语，口语中通常用who代替whom。
如：The boywhobroke the window is called Tom. (作主语，指人)
The person towhomyou talked just now is Mr Smith. (作宾语，指人)
宾语从句
用作宾语的从句叫做宾语从句。
引导宾语从句的词有：连词that, whether, if；连接代词who, whose, what, which；连接副词when, where, how, why等。
如：I doubtwhetherhe will succeed.
I wonderwhathe’s writing to me about.
I’ll tell youwhyI asked you to come.
注意：
1.宾语从句既可跟在及物动词后面，也可跟在介词后，还可跟在形容词后。
如：I don’t knowwho all the people are.
Please find outwhen the ship sails for New York.
He was afraidthat the other kids would laugh at him.
2.当宾语从句后有宾语补足语时，则需要用it做形式宾语，而将宾语从句后置。
如：I finditstrangewhat she said at the meeting.
We have madeitclearthat we will learn to deal with various difficult problems.
宾语从句例句详解
1. that引导
We believe that he is honest.我们相信他是诚实的。
The doctor insists that I give up smoking医生坚持要我戒烟。
I suggest that we should go tomorrow.我建议我们明天走。
I suggested that we should go the next day.我建议我们第二天走。
We learnt from his letter that he was in Spain.从他的信里我们了解到他在西班牙。
The seller demanded that payment should be made within five days.卖方要求5日内付款。
2. whether / if引导
I don’t know whether he’ll arrive in time.我不知道他是否能及时到。
I didn’t know whether they liked the place.我不知道他们是否喜欢这个地方。
I’ll see whether I can induce him to accept it.我要看看我是否能劝他接受。
I asked her whether she agreed.我问她是否同意。
He enquired if her parents spoke Spanish.他问她父母是否讲西班牙语。
I wonder if it’s large enough.我不知道它是否够大。
She didn’t say if he was still alive.她没说他是否还活着。
3.连接代词引导
I don’t know who [whom] you mean.我不知道你指谁。
Please tell me which you like.告诉我你喜欢哪一个。
I’Il do whatever I can do.我将做我所能做的事。
You can take whichever you like.你爱拿哪个就拿哪个吧。
We’ll do whatever we can to save him.我们将尽我们所能来挽救他。
Take whichever seat you like.你要坐哪个座就坐哪个座位。
Give it to whoever you like.你把它爱给谁就给谁。
You don’t know what you are talking about.你在说什么，你自己也不知道。
Tomorrow at this time we’ll know who is elected.明天这时候我们就会知道谁当选了。
4.连接副词引导
He asked why he had to go alone.他问他为什么必须一个人去。
You don’t know when you are lucky.你身在福中不知福。
I asked how he was getting on.我问他情况怎样。
He knows where they live.他知道他们住哪里。
Have you found out how wide the ditch Was?你了解到那条沟有多宽吗?
I’d like to know when they will let him out.我很想知道他们什么时候会放他出来。
We didn’t know why he had answered in that fashion.我们不明白他为什么这样回答。