在定语从句中，省略关系代词几种情况归纳如下

【1】关系代词作宾语时的省略

当关系代词who, whom, which和that在定语从句中用作动词宾语或介词位于句末时的介词宾语时，可以省略。

Is there anything you wanted?

想要什么东西吗?

Who is the man you were talking to?

刚才和你讲话的人是谁?

The man we saw yesterday is Mr. Brown

我们昨天看见的那个人是布郎先生。

The girl I work with is coming.

和我一块工作的那个女孩过来了。

The picture you are looking at was painted by a friend of mine.

你正在看的那幅画是我的一个朋友画的。

（备注：直接放在介词后作宾语的关系代词不可以省略。)

【2】关系代词作表语时的省略,当关系代词that在定语从句中用作表语时，可以省略。

China is not the country it was. 

中国已不是过去的中国了。

He is not the man he was when I was him first.

他不是我第一次看到他是的那个人了。

He is all a teacher should be.

他是教师的典范。

【3】关系代词作宾补时的省略,当关系代词that在定语从句中用作宾语补足时，可以省略。

I’m not the madman you thought me. 

我并不是你所认为的那个疯子。

【4】关系副词when的省略,用作时间状语的关系副词when通常不能省略，但有一种特殊情况，即用于day, year, time等少数几个词后时可以省略。

That was the year I first went abroad.

就是那一年我第一次出国了。

I’ll never forget the day we met.

我永远也忘不了我们见面的那一天。

Do you still remember the day we first met?

你还记得我们第一次见面的那一天吗？

By the time he was fourteen, Einstein had learned advanced mathematics all by himself.

14岁时，爱因斯坦已经自学了高等数学。

【5】关系副词where的省略,用作地点状语的关系副词where通常不能省略，但有一种特殊情况，即用于place, somewhere, anywhere, everywhere, nowhere少数几个词后时可以省略。

This is the place they met yesterday.

这就是他们昨天碰头的地方。

Have you somewhere I can lie down for an hour?

你有没有一个什么地方可以让我躺一个小时?

This is the place ( where ) we met years ago.

这是我们几年前见面的地方。

【6】关系副词why的省略,关系副词why通常只用于the reason后引导定语从句，且通常可换成that或for which，均可省略。

That’s the reason he came. 这就是他来的原因。

Give me one reason we should help you.

给我举出一个我们应当帮助你的理由

The reason he was fired is not difficult to explain.

他被解雇的的原因不难解释。

【7】当句首或句尾有who/there/here/that/it is /was 时，作方语的关系代词可以省略。该情况主要用于口语。

Who was it  said so?

谁那么说的？

Here is somebody wants to see you.

这里有人要见你。

This is the best dictionary there is in this library.

这是该图书馆最好的字典。

There is a man downstairs  wants to see you.

楼下有人要见你。

【8】在诗歌或谚语中，往往没有先行词。

 Who never climbs will never fall.

 不登高不跌跤。（要前进就会有挫折）

【9】the way先行词在定语从句充当方式状语以及在定语从句充当宾语时，也可以省略。

I don't like the way she is talking to me.

我不喜欢她和我说话的方式。

【10】在定语从句时态为进行时态时，可以将定语从句关系代词和助动词be一起省略，只保留现在分词。

The man talking to the teacher is my father

=The man who is talking to the teacher is my father.（动态动词进行时表示主动进行含义）

正在和老师讲话的那个人是我爸爸。

She needs one house facing south.

=She needs one house which faces south.

（静态动词进行时只表示主动含义）

【11】 在定语从句被动语态时，可以将定语从句关系代词和助动词be一起省略，只保留现过去分词。

The novels written by Lunxun are very popular among the young people.

=The novels which were written by Lunx are very popular among the young people.

鲁迅写的小说在年轻人当中很受欢迎。