定语从句语法知识点汇总（优秀9篇）

Heisthebestgeneralwhomakesthefewestmistakes。─Hamilton错误犯得最少的将军就是最好的将军。以下是人见人爱的小编分享的9篇《定语从句语法知识点汇总》，亲的肯定与分享是对我们最大的鼓励。

英语定语从句语法解析 篇一

1.先行词为all, anything, something, nothing, everything, much, little, none等不定代词时，关系代词一般只用that，不用which。在大多数情况下that可以省略。

Please tell me everything you know about the matter.

Thats all we can do at the moment.

2.as引出的限制性定语从句

在such as的结构中as可作关系代词，引出限制性定语从句。有时和same连用，在从句中可作主语、宾语或表语等。

Such people as were recommended by him were reliable.

Ive never seen such a talented young man as he is.

I have the same trouble as you 。

3.as引出的非限制性定语从句

as可作关系代词引出非限制性定语从句，代替整个主句，通常译为（正)如一样，(正）象一样等。as引导的从句一般用逗号与主句隔开，可以位于主句的前面、中间或后面。

I live a long way from work, as you know.

She did not, as her friend had feared, break down.

As is generally accepted, economic growth is determined by the smooth development of production.

4.分隔式定语从句

定语从句一般紧跟在先行词之后，但有时会被其他句子成分与先行词隔开，从而构成分隔式定语从句。

判断关系代词与关系副词 篇二

方法一： 用关系代词，还是关系副词完全取决于从句中的谓语动词。及物动词后面无宾语，就必须要求用关系代词；而不及物动词则要求用关系副词。例如：

This is the mountain village where I stayed last year.

I'll never forget the days when I worked together with you.

判断改错（注：先显示题，再显示答案，横线；用不同的颜色表示出。）

(错) This is the mountain village where I visited last year.

(错) I will never forget the days when I spent in the countryside.

（对) This is the mountain village (which） I visited last year.

（对) I'll never forget the days (which） I spent in the countryside.

习惯上总把表地点或时间的名词与关系副词 where, when联系在一起。此两题错在关系词的误用上。

方法二： 准确判断先行词在定语从句中的成分（主、谓、宾、定、状），也能正确选择出关系代词/关系副词。

例1. Is this museum ___ you visited a few days age?

A. where　B. that　 C. on which　 D. the one

例2. Is this the museum ____ the exhibition was held.

A. where　　B. that　 C. on which　　D. the one

答案：例1 D，例2 A

例1变为肯定句： This museum is ___ you visited a few days ago.

例2变为肯定句： This is the museum ___ the exhibition was held.

在句1中，所缺部分为宾语，而where, that, on which都不能起到宾语的作用，只有the one既做了主句的表语，又可做从句的宾语，可以省略关系代词，所以应选D。

而句2中， 主、谓、宾俱全，从句部分为句子的状语表地点，既可用副词where，又因 in the museum词组，可用介词in + which 引导地点状语。而此题中，介词on 用的不对，所以选A。

关系词的选择依据在从句中所做的成分，先行词在从句中做主、定、宾语时，选择关系代词 (who, whom, that, which, whose)； 先行词在从句中做状语时，应选择关系副词 （ where 地点状语，when 时间状语，why 原因状语） 。

英语定语从句语法解析 篇三

1. 分隔定语从句。

先行词与定语从句之间有时也会插入别的成分，构成先行词与定语从句的隔离，这种从句叫分隔定语从句。例如：

This is the article written by him that I spoke to you about.

He was the only person in this country that was invited.

①因定语从句过长，为使句子保持平衡，常将定语从句和其所修饰的名词或代词分开。

The film brought the hours back to me when I was taken good care of in that faraway village.

②在定语从句中使用“插入语”以增加语言的灵活性。

The pen I thought I had lost is on my desk，right under my nose.

2. as 和 which 引导的定语从句。

① as 有“正如，就像”之意，在非限制性定语从句中充当主语、宾语或表语，从句可位于主句的前面、中间或后面，一般用逗号与主句隔开。

As we had expected，her performance was wonderful.

A panda， as we know，is a lovely animal.

Tom is the tallest in our class，as you know.

但 which 引导的非限制性定语从句一般只能放在主句之后。例如：

The result of the experiment was very good，which we hadn’t expected.

②在主谓宾结构的非限制性定语从句中，which 和 as 作宾语时可互换使用。

He was an Englishman，which / as I knew from his accent.

作主语时通常用 which ，而不用 as 。但在“主语 +be+done ”结构中，as 作主语。例如：

He passed the examination，as was known.

③ as 引导非限制性定语从句时，通常用在表示肯定意义的从句中，而不能用在表示否定意义的从句中； which 则不受此限制。例如：

Mummy treats me just as a baby，which （不用 as ） I can’t bear.

She married again，which （不用 as ）was unexpected.

④在宾补结构的非限制性定语从句中，作主语或宾语时，宜用 which ，而不用 as 。例如：

He believed in God，which （不用 as ） I find strange.

He changed his mind，which （不用 as ） made me very angry.

⑤定语从句中动词若为表示知觉的词，如 see ，expect ，say ，know 等时，用 as 而不用 which 。

As we expected / know， Xiao Ming took the first place in the game.

⑥ as 引导的定语从句与 it 作形式主语的主语从句和以 what 引导的主语从句的区别。试比较：

As is known to everybody，the moon travels round the earth once every month.

It is known to everybody that the moon travels round the earth once every month.

What is known to everybody is that the moon travels round the earth once every month.

3. 定语从句与并列句的识别。

定语从句与主句之间要用“逗号”分隔，并且不能加入 and ， but ， so 等连接词。并列句一般由 and ， but ， so 等词连接，或中间用“分号”隔开。例如：

He paid the boy $10 for washing the windows，most of which hadn’t been cleaned for at least a year. （定语从句）

He paid the boy $10 for washing the windows，and most of them hadn’t been cleaned for at least a year. （并列句）

He paid the boy $10 for washing the windows；most of them hadn’t been cleaned for at least a year. （并列句）

Recently I bought an ancient Chinese vase，the price of which was reasonable. （定语从句）

Recently I bought an ancient Chinese vase；the price of it was reasonable. （并列句）

John’s parents kept telling him that he should work hard，but it didn’t help. （并列句）

4. that 引导的定语从句与结果状语从句的区别。

This is so interesting a book that all of us want to read it. （ so …… that 引导的结果状语从句）

This is so interesting a book as all of us want to read. （ as 引导的定语从句）

通过以上两个例句不难看出， so …… that 引导结果状语从句，而定语从句中先行词前有 so ， such ， the same 修饰时，常用“ as ”来引导定语从句。

5. 定语从句与同位语从句的区别。

同位语从句是位于名词 answer ， belief ， doubt ， decision ， explanation ， fact ， hope ， idea ， information ， news ， order ， problem ， promise ， truth 等后的句子，并对这些句词进行补充说明或解释；从句一般是一个完整的句子，引导词 that 只起引导作用，不作句子成分，且 that 不可省略；同位语从句不可用 which 引导。而定语从句通常是一不完整的句子，缺少主语或宾语等。作宾语时， that 可省略。

The fact that she hasn’t known the result of the examination is clear. （同位语从句）

The fact （that / which） she told me yesterday is very important. （定语从句）

「巩固性练习」

1、 _________ is mentioned above， the number of the students in senior high school is increasing.

A. As B. It C. That D. What

2、 Now Children like to go to the fast food restaurant， _________ as the name says， eating doesn’t take much time.

A. which B. that C. what D. where

3、 Sometimes the earthquake is so violent that it can destroy the whole city， _________ happened in Tang Shan in 1976.

A. as B. that C. where D. like

4、 Recently my father bought a Chinese painting， _________ was very reasonable.

A. the price of it B. which price

C. the price of which D. its price

5、 We will be shown around the city： schools， museums， and some other places， _________ other visitors seldom go.

A. what B. which C. where D. when

6、 We were next-door neighbors for three years， during ________ time we met only twice.

A. which B. this C. in which D. same

7、 Living in the central Australia desert has its problems， _________ getting water is not the least.

A. as B. for what C. of which D. for what

8、 We should do more such exercises in the future， I think， ________ those we did yesterday.

A. as B. which C. that D. it

9、 Gone are the days _________ we spent together in the village.

A. that B. when C. in which D. on which

10、 He failed his exam， _________ proves that he wasn’t working hard enough.

A. as B. which C. that D. A and B

11、 He must be from Africa， _________ can be seen from his skin.

A. that B. as C. who D. what

「参考答案」

1、 A 2. D 3. A 4. C 5. C 6. A

7、 C 8. A 9. A 10. D 11. B

英语定语从句语法解析 篇四

1)介词后面的关系词不能省略。

2)that前不能有介词。

3)某些在从句中充当时间，地点或原因状语的介词+关系词结构可以同关系副词when 和where 互换。例如：

This is the house in which I lived two years ago. 这是我两年前住过的房子。

This is the house where I lived two years ago.

Do you remember the day on which you joined our club? 还记得你加入我们俱乐部的那一天吗？

Do you remember the day when you joined our club?

18.6 as, which 非限定性定语从句

由as, which 引导的非限定性定语从句，as和which可代整个主句，相当于and this或and that。As一般放在句首，which在句中。例如：

As we know, smoking is harmful to ones health. 如我们所知，吸烟有害健康。

The sun heats the earth, which is very important to us. 太阳使地球暖起来，这对我们人类很重要。

典型例题

1)Alice received an invitation from her boss, ___came as a surprise.

A. it B. that C. which D. he

答案C. 此为非限定性从句，不能用 that修饰，而用which.，it 和he 都使后句成为句子，两个独立的句子不能单以逗号连接。况且选he句意不通。

定语从句例句 篇五

限制性定语从句

Can you tell me the date on which the accident happened?

你能告诉我这起事故发生的日期吗？

Here is the young man about whom we have heard so much.

这就是我们经常听说的那位年轻人吗？

The school where /in which we are studying is callled the First Middle School.

我们就读的那所学校叫第一中学。

We’ll go to the place where /at which the accident happpened.

我们将要去事故发生的那个地方。

The way in which you are doing it is completely crazy.

你做这件事的方式非常疯狂。

The boss in whose department Mr. King worked had heard about the accident.

金先生工作部门的经理听说了关于这次事故的情况。

This is the book for which you asked.

这就是你要的那本书。

The man who talked to you just now is an engineer.

刚才和你说话的那个人是一位工程师。

I enjoyed the evening that we spent together by the sea.

我们一起在海边度过的那个晚上，我过的很愉快。

Here is the pen that you lost the day bofore yesterday.

这是你前天丢失的那支笔。

He is the person I meet in the park yesterday.

他就是我昨天在公园里遇到的那个人。

The lady who came to our class is from Australia.

那位来过我们班的女士来自澳大利亚。

The man who shook hands with our teacher just now is Li Lei’s father.

刚才和我们老师握手的那个人是李雷的父亲。

The book you need is sold out.

你需要的那本书卖完了。

I’ll never forget the summer holiday I spent with you.

我绝不会忘记和你一起过的那个暑假。

She is one of the students in our class who are good at English.

她是我们班上英语很好的学生之一。

He is the only one of my friends who comes from a foreign country.

他是我唯一一个来自外国的朋友。

That is the place which they just now talked about.

那就是他们刚才讨论的地方。

You can keep any books that you find.

你可以保留你找到的任何书。

Is this the only thing that he does for his daughter.？

那就是他为女儿做的唯一一件事吗？

The storybook I have just read cannot be easily forgotten.

我刚才看到的那本故事书不容易忘记。

Do you know the person I spoke to just now?

你认识刚才和我说话的那个人吗？

The first lesson that Miss Lee gave us in the school is unforgettable.

李老师在学校给我们上的第一节课令人难忘。

Everything that we saw there was interesting.

我们在那儿看到的东西都很有趣。

Who is the lady that is standing over there withAnn?

何安一起站在那儿的那位女士是谁？

Wuhan is the hottest city that I have been to.

武汉是我去过的最热的城市。

I’m interested in all that I have seen。

我对我所看到的一切都很感兴趣。

Is he the man that talked with your teacher yesterday?

他就是昨天与你老师谈话的那个人吗？

Have you got the book that you need。

你得到你需要的那本书吗？

She was not on the train which arrived just now.

她不在刚到的这趟火车上。

It sounded like a truck that was going by my house.

听上去像是一辆卡车正从我家旁边经过。

Have you got something that he wanted。

你有他要的东西吗？

It is the sillest argument that I have heard.

那是我听过的最愚蠢的争论。

He wants the same book that I have.

他想要我有的那本书。

The first thing that she would do is to have her hair fixed.

她应当做的第一件事情是做个发型。

The passengers and the suitcases that were still waiting had to be transferred to another place.

仍在等待的乘客和行李只得被转移到另一架飞机上。

I will tell you all that I know.

我会把我知道的一切都告诉你。

The very thing that brought about a complete change in her life was the liberation.

正是解放给她的命运带来了彻底的转变。

That is the very thing I’ve been looking for.

那正是我要找的东西。

This is the same girl that came to borrow an English book two days ago. 这个女孩就是两天前来借英语书的那个。

Rose told me all that had happened to Oliver.

露西把奥利佛所发生的事情都告诉了我。

Because of my poor memory,everything that you told me has been forgotten.

由于我的记忆力不好，你告诉我的所有事情都忘记了。

Is there anything that I can do for you?

有什么需要我帮忙的吗？

These are the happiest hours that we have ever spent.

这些都是我们曾一起度过的最快乐的时光。

There’s no film that you ‘ll feel interested in.

没有你会感兴趣的。电影。

Mr. Liu wants to talk to the students whose homework has not been handed in.

刘老师要和那些没有交作业的学生谈话。

Can you tell me the name of the factory you visited last week.

你能告诉我上星期你参观的那家工厂的名字吗？

I don’t like the way you speak to her.

我不喜欢你对她说话的方式。

The most important thing that we should pay attention to is the first thing that I have said.

我们应该注意的最重要的事情就是我说过的第一件事。

She spent the whole evening talking about things and people that none of us had heard of.

她整晚都在谈论那些我们谁也没听说过的人和事。

He makes good use of the time that he can spare.

他充分利用他能抽出来的时间。

He is the only one of the three who has got the new idea.

他是三个人中惟一一个想到了这个新主意的人。

All that are present burst into tears.

所有到场的人都突然大哭起来。

He was the only person in his company that was invited.

他是他那个公司里惟一一个被邀请的人。

The people that were mentioned by him were honest.

他所提到的那些人都很诚实。

I shall do it in the same way that you did.

我要按你的方法去做。

Anyone who does this kind of job shouldn’t be careless.

谁干这种工作，谁都疏忽不得。

Who that has seen him doesn’t like him.

见过他的人谁不喜欢他呢？

Which is the magazine that you borrowed yesterday?

哪本是你昨天借的杂志？

I’ll tell you all that I know

我会把我知道的一切都告诉你。

This is the best movie that I have ever seen

这是我看过的最好的电影。

You can take any room that you like.

你随便要哪个房间都行。

Guilin is a beautiful place that people from all over the world want to visit.

桂林是个漂亮的地方，全世界的人们都想去游览。

There are moments when I forget all about it

有时候我完全忘记了这一切。

The film brought the hours back to me when I was taken good care of in that far-away villiage.

这部电影使我想起了我在那个遥远的村庄里被悉心照顾的那段时光。

My girl friendtold me that December 20 is the day when she was born

我的女朋友告诉我说12月20日是她出生的日子。

He will never forget the day when he began to learn English.

他永远不会忘记他开始学英语的那一天。

July and August are the months when the weather is cold in New Zealand.

七，八月份是新西兰天气很冷的月份。

Do you stilll remember the hours when we had a party in the park?

你还记得那次我们在公园开晚会的时光吗？

Don’t you remember that day when we first came here?你不记得我们第一次来这儿的那一天了吗？

I can never forget the days when we worked together and the days we spent together.

我永远忘不了我们一起工作和一起度过的时光。

This is the house where I once lived.

这就是我曾经住过的房子。

The town where my father grew up is not far from here.

我爸爸长大的那个小镇离这儿不远。

After living in Paris for fifty years he returned to the small town where he grew up as a child.

在巴黎生活50年后，他回到了儿时生活的那个小镇。

You should make it a rule to leave things at a place where you can find them again.

你应该定下个规矩把东西放在你以后能找着的地方。

The house in which I spent my childhood isn’t far away.

那间让我度过了童年的放在离这儿不远。

“The days when /on which I met that famous pop star was the greatest of my life.”said the fan.

这位歌迷说：“见到这位著名歌星的那天是我一生最棒的日子。”

In the dark street ，there wasn’t a single person to whom she could turn for help.

在黑暗的街道上，没有一个她可以寻求帮助的人。

非限制性定语从句

In fact the Swede didn’t understand the threee questions,which were asked in French.

事实上，那位瑞典人不理解那三个用法语问的问题。

Tracy was always speaking highly of her role in the play, which,of course ， made the others unhappy.

特雷西总是夸耀她在戏中的角色，这当然令其他人不高兴。

He marrried her,which was natural.

他和她结婚了，这是很自然的事。

He said he had never met her,which is not true.

他说他从未见过他，这不是真的。

The weather turned out to be very good,which we hadn’t expected.

结果天气非常好，这是我们没有预料到的。

I tried to get out of the business,which I found impossible.

我试图从这件事中脱身出来，但我发觉这很难。

I have bought such a watch,which was advertised on TV.

我买了一块手表，它在电视上做了广告的。

He succeeded in the compotition,which made his parents very happy.

他在竞赛中取得了成功这让他的父母非常高兴。

This summer I want to go to Hangazhou, where there is a beautiful lake.

这个夏天我想去杭州，那里有个美丽的湖。

Miss Green woirks in a hospital,which is only a 10-minute walk from here.

格林小姐在医院工作，那里离这儿只有10 分钟的路程。

I came to London,where I found him

我来到了伦敦，在那儿我找到了他。

Tom hid himself behind the door ，from where he could hear the steps of his mother clearly.

汤姆藏在门背后，从那里他能清楚的听到他妈妈的脚步声。

She will never forget September 1,when she had her first history lesson as a teacher.

她永远也不会忘记9月1日。那天她第一天当老师，上的是一节历史课。

Mery Smith,who is standing on the cornber,wants to meet you.

玛丽．史密斯—在那个角落里站着的那个人——想见你。

Her brother,who is a teacher,is strict with her.

她的哥哥是位老师，对她要求很严格。

We shall have to make a decision about Ms.King ，whose story I’ve just told you.

关于金女士，我们得做个决定，她的情况我刚才已经告诉你们了。

Have you seen the film, whose leading actor is world famous?

你看过《泰坦尼克号》吗？片中的男主角世界闻名。

He paid the boy $50 for washing ten windows,most of which had not been cleaned for at least a year.

他付给那个男孩50美元洗10个窗子，大部分窗子至少有一年没有洗了。

Mr. Brown has written a novel,the name of which I’ve completely forgotten.

布朗先生写了一部小说，书名我完全忘记了。

Mr. White wrote many articles ，some of which were translated into Chinese.怀特先生写了不少文章，其中一些被译成了中文。

He has some novels,all of which are written in Russian.

他有一些小说，都是用俄语写的。

This kind of book is for children,the native language of whom is Chinese.

这种书是供母语是汉语的儿童看的。

定语从句归纳及用法 篇六

定语从句在初中英语中的重要性主要体现在完形、阅读和写作中，因此，能否较好的掌握定语从句直接关系到你英语成绩的拔高。其实，定语从句并不难。

一。 定语从句的概念

在复合句中，修饰某一名词或代词的从句叫定语从句。被修饰的名词或代词叫先行词，引导定语从句的词叫关系词，定语从句一般放在先行词的后面。

二。 引导定语从句的关系词

引导定语从句的关系词有关系代词和关系副词，常见的关系代词包括that， which， who（宾格whom，所有格whose）等，关系副词包括where， when， why等。关系代词和关系副词放在先行词及定语从句之间起连接作用，同时又作定语从句的重要成分。

三。 定语从句的分类

根据定语从句与先行词的关系，定语从句可分为限制性定语从句及非限制性定语从句。限制性定语从句紧跟先行词，主句与从句不用逗号分开，从句不可省去。非限制性定语从句与主句之间有逗号分开，起补充说明作用，如省去，意思仍完整。

四。 关系代词的用法

1、 that 既可以用于指人，也可以用于指物。在从句中作主语、宾语或表语。作主语时不可省略，作宾语可省略。例如：

Mary likes music that is quiet and gentle.

玛丽喜欢轻柔的音乐。（that作主语）

The coat （that） I put on the desk is blue.

我放在桌子上的那件外套是蓝色的。（that作宾语）

2.which用于指物，在句中作主语、宾语或表语。作主语不可省略，作宾语可省略。例如：

The building which stands near the train station is a supermarket.

位于火车站附近的那座大楼是一家超市。（作主语）

The film （which） we saw last night was wonderful.

我们昨天晚上看的那部电影很好看。（作宾语）

3.who， whom用于指人，who 用作主语，whom用作宾语。在口语中，有时可用who代替whom。who和whom作宾语时也可省略。例如：

The girl who often helps me with my English is from England.

经常在英语方面帮助我的那个女孩是英国人。（作主语）

Who is the teacher （whom） Li Ming is talking to？

正在与李明谈话的老师是谁？（作宾语）

注意：

（1）当定语从句中含有介词，介词放在句末时，who，whom，that， which可省略，但介词在关系代词前时，只能用介词+which/whom结构。例如：

This is the house in which we lived last year.

这是我们去年居住的房子。

Please tell me from whom you borrowed the English novel.请告诉我你从谁那借的这本英文小说。

（2）含有介词的固定动词词组中，介词不可前置，只能放在原来的位置上。例如：

This is the person whom you are looking for.

这就是你要找的那个人。

（3）that 作介词的宾语时，介词不能放它的前面，只能放在从句中动词的后面。例如：

The city that she lives in is very far away.

她居住的城市非常远。

（4）关系词只能用that的情况：

a. 先行词被序数词或形容词最高级所修饰，或本身是序数词、基数词、形容词最高级时，只能用that，而不用which.例如：

He was the first person that passed the exam.

他是第一个通过考试的人。

b. 被修饰的先行词为all， any， much， many， everything， anything， none， the one等不定代词指物时，只能用that，而不用which.例如：

Is there anything that you want to buy in the shop？

你在商店里有什么东西要买吗？

c. 先行词被the only， the very， the same， the last， little， few 等词修饰时，只能用that，而不用which.例如：

This is the same bike that I lost.

这就是我丢的那辆自行车。

d. 先行词里同时含有人或物时，只能用that， 而不用which.例如：

I can remember well the persons and some pictures that I saw in the room.

我能清楚记得我在那个房间所见到的人和一些照片。

e. 以who或which引导的特殊疑问句，为避免重复，只能用that.例如：

Who is the girl that is crying？

正在哭泣的那个女孩是谁？

f. 主句是there be 结构，修饰主语的定语从句用that，而不用which，例如：

There is a book on the desk that belongs to Tom.

桌子上那本书是汤姆的。

（5）关系词只能用which，而不用that 的情况：

a. 先行词为that， those时，用which， 而不用that.例如：

Whats that which is under the desk？

在桌子底下的那些东西是什么？

b. 关系代词前有介词时，which，而不用that.例如：

This is the room in which he lives.

这是他居住的房间。

c. 引导非限制性定语从句，先行词指事物时，用which， 而不用that，例如：

Tom came back， which made us happy.

汤姆回来了，这使我们很高兴。

五。 关系副词的用法

1、 when指时间，其先行词表示时间，when在定语从句中作时间状语。例如：

This was the time when he arrived.

这是他到达的时间。

2、 where指地点，其先行词表示地点，where在定语从句中作地点状语。例如：

This is place where he works.

这是他工作的地点。

3、 why 指原因，其先行词是原因，why在定语从句中做原因状语。例如：

Nobody knows the reason why he is often late for school.

没人知道他为什么上学总迟到。

as, which 非限定性定语从句 篇七

由as, which 引导的非限定性定语从句，as和which可代整个主句，相当于and this或and that。As一般放在句首，which在句中。

As we know, smoking is harmful to one's health.

The sun heats the earth, which is very important to us.

典型例题

1)Alice received an invitation from her boss, ___came as a surprise.

A. it　 B. that　 C. which　　D. he

答案C. 此为非限定性从句，不能用 that修饰，而用which.，it 和he 都使后句成为句子，两个独立的句子不能单以逗号连接。况且选he句意不通。

2)The weather turned out to be very good, ___ was more than we could expect.

A. what　B. which　C. that　D. it

答案B。which可代替句子，用于非限定性定语从句，而what不可。That 不能用于非限定性定语从句，it不为连词，使由逗号连接的两个句子并在一起在英语语法上行不通。

3)It rained hard yesterday, ____ prevented me from going to the park.。

A. that　B. which　　C. as　 D. it

答案B.

as 和which在引导非限制性定语从句时，这两个关系代词都指主句所表达的整个意思，且在定语从句中都可以作主语和宾语。但不同之处主要有两点：

（1） as 引导的定语从句可置于句首，而which不可。

（2） as 代表前面的整个主句并在从句中作主语时，从句中的谓语必须是系动词；若为行为动词，则从句中的关系代词只能用which.。

在本题中，prevent由于是行为动词，所以正确选项应为B。

As 的用法

例1. the same… as;such…as 中的as 是一种固定结构， 和……一样……。

I have got into the same trouble as he (has)。

例2. as可引导非限制性从句，常带有'正如'。

As we know, smoking is harmful to one's health.

As is know, smoking is harmful to one's health.

As是关系代词。例1中的as作know的宾语；例2中，它充当从句的主语，谓语动词know要用被动式。

什么叫做定语从句 篇八

1. think it + adj + that

在讲今天的语法之前，我们回顾一下平时同学们在写作以及阅读中可能比较疑惑的例句：

I think it important that you tell your mother the truth.

疑惑之处在于，it后面为什么没有is?

例句采用了这样的句型：“think it + adj”。此处，it为形式宾语，that引导的宾语从句才是真实宾语，而important是宾语补足语。所以，it是形式宾语而不是主语，不需要加be动词。

一般情况下，各位更熟悉的句型是：“I think (that) it is important that.。. ”；这两者都是正确的，注意区分和辨别。

感兴趣的同学还可以去这个网站看看：English Language & Usage。它给出了以下几个类似的例句：

e.g. We do not think it necessary to go.

e.g. Some people do not think it important to be thrifty.

2. 定语从句中的that

定语从句中比较容易处理方面是，定语从句中“that”多可省略，表现为关系代词作宾语的情况：

e.g. He must be the man (that) you have been looking for.

此处，man作looking for的宾语。

至于不可省略的that，这里小编只举两例，算是比较常用的规则哦：

（1）紧接着上面阐述，除了关系代词作宾语的情况外，其余时候多不能省略that。比如小编给各位找来一个作主语的例子，各位可以举一反三：

e.g. All that glitters is not gold.（发光的未必都是金子。）

此处，that指代主语，不可以省略。

（2）我们都知道that引导定语从句，可指人也可指物，算是兼有“who”和“which”的作用；但当定语从句修饰的先行词既有人又有物时，那么就只能用that且不可省略了。

e.g. I still remember the things and persons that I met when I traveled to Tibet.

接下来再给各位同学出一道题检验一下今天学习的知识点到底掌握了没有，题目如下：

This is the fastest train that there is to Beijing.

上句话中的that是否可以省略？

A. yes

B. no

答案：A、可以省略。

（1）首先我们来判断一下此处that引导的从句在句子中是什么成分：

This is the fastest train that there is to Beijing 。

由于there be句型的特殊性，并不是跟在be动词后面的就一定是宾语，there be句型本身就是一个倒装。这种句型之所以要用there作引导词，而把主语置于动词之后，是为了使主语成为信息中心，以达到引出新话题的目的。上述例句中的train是定语从句中的主语成分。

（2）认真学习的同学肯定还记得上期小编总结了一句“定语从句中that多可省略，表现为关系代词作宾语的情况”，因此各位就倾向于记住宾语之外的成分都不可以省略that，但there be结构却是特例。具体语法点为：在there be结构中出现定语从句，或在定语从句中出现there be时，用作主语的关系代词也可省略。

（3）因此，上述例句中的train虽作从句的主语成分，但由于there be结构的特殊性，that仍旧可以省略。此处特例建立在固定结构的用法基础上，也算是有规律可循的特例了。

什么叫做定语从句 篇九

要学定语从句，得知道什么是定语。定语是用来限定、修饰名词或代词的。例如，a good book, good就是定语。那么复合句中修饰名词或代词的从句就叫做定语从句。定语从句由关系代词或关系副词引导，相当于形容词，在句中作定语。被定语从句修饰的词叫先行词，定语从句一般放在先行词的后面。引导定语从句的关联词称为关系词，关系词有关系代词和关系副词。关系代词有that, which, who, whom, whose等，绝对没有what；关系副词有where, when, why,how等。关系词放在先行词和定语从句之间，起连接作用，同时又作定语从句的某个成分。

一、关系代词引导的定语从句

1、由who, whom, that，Whose引导的从句

这些词代替的先行词是人的名词或代词，who作主语指人，whom作宾语指人，that既可作主语又可作宾语（作宾语可以省略），可以指人也可以指物。Whose 用来指人或物，只用作定语。

（1） Is he the man who/that wants to see you? 他是那个想见你的男人吗？（who/that在从句中作主语）

（2） He is the man whom/ that I saw yesterday. 他就是我昨天见的那个人。（whom/that在从句中作宾语）

（3） The man whom you spoke to just now is our English teacher 你刚刚说话的那个男人是我们的英语老师

（4） he man whose son is a doctor is our professor. 那个儿子是医生的男人是我们的教授。

2、由which, that引导的从句

它们所代替的先行词是事物的名词或代词，在从句中可作主语、宾语等，作宾语时可以省略，例如：

（1） Prosperity which / that had never been seen before appears in the countryside. 农村出现了前所未有的繁荣。（which / that在从句中作主语）

（2） The package (which / that) you are carrying is about to come unwrapped. 你拿那个包裹快要散开了。(which / that在从句中作宾语）

注意： 代表物时多用which，但在下列情况中用that而不用which：

a)先行词是anything, everything, nothing ， none等不定代词时；

b)先行词由every, any, all, some, no, little, few, much等修饰时，这时的that常被省略；

c)先行词前有序数词或被形容词最高级修饰时；

d)先行词中既有人又有物时；

e)整个句中前面已有which，who,that时；

f)当先行词为物并作表语时；

g)先行词为one时；

h)先行词同时又被the only,the very,the same修饰时；

二、关系副词引导的定语从句

1、when指时间在定语从句中做时间状语也可做连接词用

I still remember the day when I first came to the school.

2、where指地点在定语从句中做地点状语 Shanghai is the city where I was born.

3、why指原因在定语从句中做原因状语 ，用在reason 后面。 Please tell me the reason why you missed the plane.

常见考法

对于定语从句的考查，多以单选的形式考查学生灵活运用的能力。一般情况下，常从关系词的意义和功能的角度考查，重点是that,which,who引导的定语从句。

典型例题：

You're the only person ______I've ever met ______could do it.

A. who B. whom C. whom D. who

解析：先行词person后有两个定语从句，第一个从句省略了关系代词whom.因为， whom作从句中met的宾语，可以省略。第二个从句who could do it.who在从句中作主语，不可省略。

答案：D

误区提醒

当表示时间或地点的名词作先行词时，要判断出它们在从句中作状语还是主语或宾语。作状语时用关系副词，反之用关系代词。

典型例题：

I can never forget the day _______ we worked together and the day ______ we spent together.

A. when; which B. which; when C. what; that D. on which; when

解析：两个先行词the day都是表示时间的名词，但第一个空白处要填的关系词在从句中作状语，因此要用关系副词when. 第二个空白处要填的关系词在从句中作动词spent的宾语，因此要用关系代词which或that来引导定语从句。

答案：A

以上就是差异网为大家带来的9篇《定语从句语法知识点汇总》，希望可以启发您的一些写作思路，更多实用的范文样本、模板格式尽在差异网。