定语从句是用来修饰一个名词或代词，进一步描述它的特征或性质的从句。这些从句通常由关系代词或关系副词引导，并且紧跟在被修饰的词后面。以下是小编为大家整理的定语从句用法（通用14篇），希望能帮到大家。
定语从句用法 1
一.定语从句及相关术语
1.定语从句：修饰某一句中的名词或代词的从句称为定语从句，一般紧跟在它所修饰的先行词后面。被修饰的词称为先行词。
2.关系词：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, as等;关系副词有where, when, why等。
关系词常有3个作用：
1，引导定语从句。
2，代替先行词。
3，在定语从句中担当一个成分。
二.关系代词引导的'定语从句
1.who指人，在从句中做主语
(1)The boys who are playing football are from Class One.
(2)Yesterday I helped an old man who lost his way.
2. whom指人，在定语从句中充当宾语，常可省略。
(1) Mr. Liu is the person (whom) you talked about on the bus.
(2) Mr. Ling is just the boy whom I want to see.
注意：关系代词whom在口语和非正式语体中常用who代替，可省略。
(3) The man who/whom you met just now is my friend.
3. which指物，在定语从句中做主语或者宾语，做宾语时可省略
(1) Football is a game which is liked by most boys.
(2) This is the pen (which) he bought yesterday.
4. that指人时，相当于who或者whom;指物时，相当于which。在宾语从句中做主语或者宾语，做宾语时可省略。
(5) The number of the people that/who come to visit the city each year
rises one million.
(6) Where is the man that/whom I saw this morning?
5. whose通常指人，也可指物，在定语从句中做定语
(1) He has a friend whose father is a doctor.
(2) I once lived in a house whose roof has fallen in.
whose指物时，常用以下结构来代替
(3)The classroom whose door is broken will soon be repaired.
(4)The classroom the door of which is broken will soon be repaired.
(5)Do you like the book whose cover is yellow? (6)Do you like the book the color of which is yellow?
三.介词+关系代词引导的定语从句
1. 关系代词在定语从句中做介词宾语时，从句常由介词+关系代词引导
(1)The school (that/which) he once studied in is very famous.
(2)The school in which he once studied is very famous.
(3)Tomorrow I will bring here a magazine (that/which) you asked for.
(4)Tomorrow I will bring here a magazine for which you asked.
(5)We’ll go to hear the famous singer (whom/that/who) we have often talk-ed about.
(6) We’ll go to hear the famous singer about whom we have often talked.
2.关系代词前的介词的选择
* 由先行词的习惯搭配或根据先行词的需要。
(1) The speed at which light travels is 300,000 km per second. (at the speed of …以…速度)
(2) The reason for which he didn’t come to school was that he was ill. (for a certain reason 由于某种原因)
* 介词可能是从句短语动词的一个固定部分或固定搭配
(3) Don’t bring children to see the animals of which they are afraid. (be afraid of 害怕)
(4) This is the teacher from whom I borrowed the book. (borrow from…从…借入
注意：1. 含有介词的动词短语一般不拆开使用，如：look for, look after, take care of等
(1) This is the watch which/that I am looking for. (T)
(2) This is the watch for which I am looking. (F)
2. 若介词放在关系代词前，关系代词指人时用whom，不可用who或者that;指物时用 which，不能用that;关系代词是所有格时用whose
(1) The man with whom you talked is my friend. (T)
(2) The man who/that you talked with is my friend. (F)
(3) The plane in which we flew to Canada is very comfortable. (T)
(4) The plane in that we flew in to Canada is very comfortable. (F)
3. “介词+关系代词”前可有some, any, none, both, all, neither, most, each, few等代词或者数词
(1) He loved his parents deeply, both of whom are very kind to him.
(2) In the basket there are quite many apples, some of which have gone bad.
(3) There are forty students in our class in all, most of whom are from big cities.
四.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
(1) I still remember the day when I first came to the school.
(2) The time when we got together finally came.
2. where指地点，在定语从句中做地点状语
(1) Shanghai is the city where I was born.
(2) The house where I lived ten years ago has been pulled down.
3. why指原因，在定语从句中做原因状语
(1) Please tell me the reason why you missed the plane.
(2) I don’t know the reason why he looks unhappy today.
注意：1.关系副词引导的从句可以由“介词+关系代词”引导的从句替换
(1) The reason why/ for which he refused the invitation is not clear.
(2) From the year when/in which he was going to school he began to know what he wanted when he grew up.
(3) Great changes have taken place in the city in which./where I was born.
2.当先行词为时间、地点、原因名词时，如果在从句中不是作状语时，不可用关系副词引导。
(1)The reason (that/which) he gave for being late is that his mother was ill.
(2)They make me think of the happy days (that/which) we spent together.
(3)Is this factory the one (that/which) they visited the day before yester- day.
定语从句用法 2
定语从句用法讲解
一、定语从句的识别
1、结构识别：名词+连接词+句子
【例句】Kevin gave us a wonderful training course, which left us a deep impression.
【解析】这个句子的前身应该是这样的：Kevin gave us a wonderful training course. It left us a deep impression. it就是指代前面这个句子，这样两个句子就有了共有的名词，连接两个具有共同名词的句子是定语从句的作用，就可以用which代替it，这样就有了示例中的非限定性定语从句。
2、常用连接词：
关系代词：who, whom, which, that, as, whose
关系连词：when, where, why, how
介词+关系代词：as和that以及who一般不能接到介词后引导句子
二、定语从句的处理方法
1、按照定语的处理方法将定语从句前置，这种处理方式适用于比较短的和起修饰限定作用的定语从句。
2、在考研中大多数的定语从句起的作用是连接句子，因此我们通常把定语从句从整个句子中独立拆分出来单独成为一个句子，这种处理方法的关键是找到连接词，拆分点就是连接词。
对于“介词+连接词”引导的定语从句，拆分点就在介词处。
【例句】There is something by virtue of which man is man.
【译文】存在一种特性，人之所以为人就是由于这种特性。
【解析】这句话其实是由以下两句话变来的：
1)There is something.
2)Man is man by virtue of this thing.这两句话中有共有的名词something和this thing，用which替换掉this thing再把of which提前，得到：There is something of which man is man by virtue
三、例句分析
【例句】Such large, impersonal manipulation of capital and industry greatly increased the numbers and importance of shareholders as a class, an element in national life representing irresponsible wealth detached from the land and the duties of the landowners; and almost equally detached from the responsible management of business.
【译文】对资本和企业的这种大规模的非个人操纵大大增加了股东作为一个阶级的数量和重要性。这个阶层作为国计民生的一部分，代表了非个人责任的财富与土地及土地所有者应尽义务的分离，而且也几乎与责任管理相分离。
【解析】句子的主干为：Such large, impersonal manipulation of capital and industry greatly increased…shareholders as a class, (which was) an element…这句话的.难点还在于其主语和宾语都有较长的短语和of结构限定，并且分句是由两个and相连的3个部分组成的。
分句an element…landowners又带有两个定语从句，一个是(which was)representing…，另一个是(which was)detached…。可见，定语从句的难点在于经常省略“引导词+be”的结构，从而在理解上容易和分词结构相混淆。实际上定语从句并不符合汉语的使用习惯。所以翻译时遇上定语从句，一定不要机械地按照原来的顺序生搬硬套。像这样分句较长的情况，把主句和分句拆为两句是比较好的方法。所以这里从“这个阶层”开始另起一句。
定语从句用法 3
定语从句用法的详解
一、定语从句的有关概念
所谓定语从句，就是在复合句中起定语作用以修饰主句中的名词或代词的从句。学习定语从句，首先要弄清两个重要概念——先行词和关系词。
先行词是我们汉语中从来没有听过的一个新概念，它其实指的就是被定语从句所修饰的词。由于定语从句修饰名词或代词时，定语从句通常是后置的，所以人们就将放在定语从句前被定语从句修饰的名词或代词叫先行词。
那什么是关系词呢？其实它就是用于引导定语从句的引导词。事实上，英语中的各类从句，不管性质如何，它们都需要有一个词来“引导”，正如人们给引导状语从句的词语取了个名字叫从属连词一样，人们也给引导定语从句的词语取了个名字，叫它关系词，因为它通常被放在先行词和定语从句之间起连接作用，以表明两者之间的修饰关系，同时它还在定语从句中充当一定的句子成分。
二、定语从句中关系词与所修饰先行词的关系
为了更好地理解定语从句，我们还有必要研究一下关系词与先行词之间的关系。但在研究这种关系之前，我们先来看看关系词有哪些。
根据关系词在定语从句中的作用，我们可以将关系词分为关系代词和关系副词两种。所谓关系代词就是指起代词作用的关系词，它们在引导定语从句的同时，还在定语从句中充当主语、宾语、宾语等，英语中比较常用的关系代词有that, which, who, whom, whose等。
类似地，关系副词就是指起副词作用的关系词，它们在引导定语从句的同时，还在定语从句中充当状语等，英语中比较常用的关系副词只有三个，即when, where和why。
许多初学定语从句的人弄不清关系词与先行词之间到底是什么关系。其实啊，关系词与先行词之间的关系很简单，简单得可以划一个等号。因为，关系词的含义在本质上等价于先行词，它与先行词指的就是同一个人或同一个事物。为便于理解，下面我们来看几个例子吧。
I know the man who lives next door.我认识住在隔壁的那个人。
这是一个含有定语从句的复合句。句中的the man为先行词，who lives next door为修饰the man的定语从句；在定语从句中，who是关系词，它在定语从句中用作主语，从意义上说，它在此所表示的意思与先行词the man等价，换句话说，上面这个句子与下面这个句子等价：I know the man. He lives next door.我认识这个人，它就住在隔壁。
She will never forget the day when she got married.她永远不会忘记她结婚的这一天。
句中的the day为先行词，when she got married为修饰the day的定语从句；在定语从句中，when是关系词，它在定语从句中用作状语，从意义上说，它在此与“介词+先行词”所表示的意思等价，也就是说上面的句子与下面这个句子等价：She will never forget the day. On that day she got married.她永远不会忘记这一天，在这一天她结婚了。
三、定语从句的翻译
许多英语初学者往往弄不明白为什么引导定语从句的关系词which不能译为“哪一个”，who不能译为“谁”，when不能译为“什么时候”，where不能译为“什么地方”，等等。
首先，我们必须要明白一点，那就是引导定语从句的which, who, when, where, why等是关系词（关系代词或关系副词），而不是疑问词，所以不能按疑问词的意思来理解。
前面我们讲到，英语中的定语从句总是后置的，即要放在被修饰名词或代词之后；但在汉语中，定语通常是前置的，也就是说定语要放在被修饰名词的前面，并通常表现为“……的”这样的形式。当我们翻译英语中定语从句的时候，一般可以按汉语习惯，将定语从句翻译在被修饰的名词或代词之前，而其中的关系词一般就是译成汉语中的“……的”。如：
He showed me the article that he had written.他把他写的文章拿给我看。
句中的that he had written为修饰名词the article的定语从句，翻译时就可译为“他写的文章”，其中的`关系代词that在此译成了“的”字。
She was not in the train which arrived just now.她不在刚到的那列火车上。
句中的which arrived just now为修饰名词the train的定语从句，翻译时就可译为“刚才到的那列火车”，其中的关系代词which在此也译成了“的”字。
Sunday is the day when very few people go to work.星期日是没什么人上班的日子。
句中的when very few people go to work为修饰名词the day的定语从句，翻译时就可译为“没什么人去上班的日子”，其中的关系副词when在此也译成了“的”字。
That’s the hotel where we were staying last summer.这就是我们去年夏天住的旅馆。
句中的when very few people go to work为修饰名词the day的定语从句，翻译时就可译为“没什么人去上班的日子”，其中的关系副词when在此也译成了“的”字。
Give me one reason why we should help you.给我举出一个我们应当帮助你的理由。
句中的why we should help you为修饰名词one reason的定语从句，翻译时就可译为“我们应当帮助你的理由”，其中的关系副词why在此也译成了“的”字。
当然，我们上面介绍的是翻译定语从句最简单同时也是最基本的方法，由于英语句子千变万化，定语从句的表现形式也灵活多样，有些含有定语从句的句子可能用此方法翻译会显得别扭，但只要掌握了这个基本的方法，再加上适当的变通，翻译定语从句也就不难了。
四、定语从句中关系代词的省略
省略关系代词最典型的情形就是当关系代词在定语从句中用作宾语的时候。在定语从句中能够用作宾语的关系代词有that, which, who, whom。如：
Those books (that) you lent me were very useful.你借给我的那些书很有用。
句中的(that) you lent me为修饰those books的定语从句，引导定语从句的关系代词that在定语从句中用作动词lent的宾语，故可以省略。
I wore the necklace (which) my mother had left me.我戴着我妈留给我的项链。
句中的(which) my mother had left me为修饰the necklace的定语从句，引导定语从句的关系代词which在定语从句中用作动词left的宾语，故可以省略。
Do you still remember the boy (who, whom) I was going out with?你还记得那个跟我约会的小伙子吗?
句中的(who, whom) I was going out with为修饰the boy的定语从句，引导定语从句的关系代词who / whom在定语从句中用作句尾介词with的宾语，故可以省略。
注意：我们说的关系代词的省略只限于限制性定语从句，在非限制性定语从句中，即使关系代词用作宾语也不能省略。另外，当关系代词直接用作介词后作宾语时，此时也不能省略。如：
I wanted to find someone with whom I could discuss books and music.我想找到一个可以和我谈书和音乐的人。
此句中的关系代词which虽然也是用作宾语，但不能省略，因为它是直接跟在介词with后面作宾语。但是，如果将此句改写一下，将介词with置于句末，则可以将关系代词whom省略。如：
I wanted to find someone (whom) I could discuss books and music with.我想找到一个可以和我谈书和音乐的人。
定语从句用法 4
一、as引导定语从句
as引导定语从句时，既可以引导限定性定语从句，又可以引导非限定性定语从句。区分as引导定语从句和其它从句的关键特征是：as引导定语从句时在从句中做成分，通常做主语或宾语。
1、as引导限定性定语从句
如从句所修饰的名词前有such、the same、as出现，后面的定语从句将由as引导，形成such...as，the same...as，as…as这样的固定结构，译为“和……一样”。
例1：I never heard such stories as he told.
我从未听过他所讲的那样的故事。
例2：He’ll repeat such questions as are discussed in the book.
他将重复书中讨论过的'问题。
例3：They made the same mistake as others would have made on such an occasion.
他们犯了和其他人在这种场合下会犯的同样错误as用法详解as用法详解。
2、as引导非限定性定语从句
as引导非限定性定语从句，往往指代一整句话，通常表示“正如”的意思。as引导的非限制性定语从句位置相对比较灵活，可以位于先行词之前、之后或中间。
例：As is known to everybody, the moon travels round the earth.
众所周知，月亮绕着地球转。
二、as引导时间状语从句
as引导时间状语从句多用于口语，强调“同一时间”或“一先一后”，有时还有“随着”的含义。
例1：As I was going out, it began to rain.
当我出门时，开始下雨了。(as强调两个动作紧接着发生，不强调下雨的特定时间。)
例2：As time goes on, he will understand what I said.
随着时间的推移，他会理解我所讲的话。
三、as引导原因状语从句
as表示“因为”，与because相比，较口语化，所表达的原因语气较弱，所表的原因比较明显，或是已知的事实。
例1：As the weather is so bad, we have to delay our journey.
因为天气太糟糕，我们不得不推迟旅行。
例2：Any new source of energy will be very welcome, as there is already a shortage of petroleum.
任何新型能源都将大受欢迎，因为石油已经出现短缺。
四、as引导方式状语从句
as表示“按照”，“以……方式”，“像……一样”，“正如”。
例：Do as the Romans do when in Rome. 入乡随俗
注：as在引导方式状语从句时，还常出现在一个固定的类比结构中：(just) as …, so…。这一句型表示类比，基本含义是“正如……，所以……”。
例：Just as virtue is its own reward, so is vice its own punishment.
善有善报，恶有恶报。
五、as引导让步状语从句
as可以表示“尽管”，“虽然”，引导让步状语从句，但必须构成倒装。让步状语从句倒装规则有两类：
1、形容词/副词/分词/名词(无冠词)/介词短语等+as+主语+谓语动词，主句。
例1：Much as I like you, I couldn’t live with you.
我尽管很喜欢你，却不能和你在一起生活。
例2：Child as he is, he knows to help others.
尽管他是个孩子，他懂得帮助别人。
2、动词原形+as+主语+助动词(may/might, will/would, can/could, do/does/did)，主句as用法详解考研英语。
例：Try as we may, we cannot sense directly the television signal sent out from the broadcast station.
尽管我们费了很大的劲，也无法直接觉察发射台发出的电视信号
六、as引导比较状语从句
as引导比较状语从句，其基本结构是as…as。前一个as是副词，后一个as是比较状语从句的连词。否定结构为not so much … as …。
例1：Small as it is, the ant is as much a creature as are all other animals on the earth.
尽管蚂蚁很小，但是它同地球上的任何其他动物一样，也是一种动物。
例2：It was not so much the many blows he received as the lack of fighting spirit that led to his losing the game.
与其说是他受到了许多打击，还不如说是缺乏斗志使他输掉了比赛。
定语从句用法 5
从句中that的用法
一、that引导名词性从句时(即主语从句、宾语从句、表语从句、同位语从句),在从句中无具体含义,只起连接作用,而且在从句中也不作任何句子成分.它所引导的从句的句子结构和意义是完整的,而且从句一般是陈述一个事实.
例如:
①Thatshe was able to come made us very happy.
她能来使我们很高兴.
②The newsthatour team has won the match is true.
我们队赢了这场比赛的消息是真的
③The reason he didnt come wasthathe was ill.
他没来的原因是他病了.
当that引导的主语从句或宾语从句太长时,常用it作形式主语或宾语而把that从句放在后面.如:
①It is well—knownthatthe earth is round.
众所周知,地球是圆的
②We find it necessarythatwe practise spoken English every day.
我们发现每天练习英语口语很有必要.
注意：
that引导的主语从句,表语从句以及同位语中,that不能省略.that引导的.宾语从句,一般可以省去that,但在下面情况中不能省略——
1.在suggest,order等表示命令、请求、建议等动词后的宾语从句中,不能省;
2.由and或but所连接的两个引导的宾语从句时,第一个从句中的that可以省,第二个从句中的that不能省;
3.that引导的宾语从句,如果从句中还有其他状语从句,引导宾语从句的that不能省略.
Tell himthatif he is at home,Ill call to see him.
二,that引导定语从句要注意以下几点:
1.定语从句中缺主语,修饰人时用who /that,修饰物时用which /that引导.如:
Is this the factory which /thatmakes TV sets
The man who /thatvisited our school is from Australia.
2.从句中缺宾语,修饰人时用 who /whom /that或省略引导词;修饰物时用which /that或省略引导词.如:
Gone are the days which /thatwe spent together in the village.
He is the man who /whom /thatI think to be worthy of our praise.
3.用that不用which的七种情况:
①先行词前有形容词最高级或序数词修饰时,用that不用which引导.如:
This is the best placethatI have ever visited.
②先行词为little,much,all,none,few,(the)one,something,everything,nothing,anything等不定代词时,用that引导.如:
There is nothing in the worldthatcan frighten him.
③先行词既有指人的名词又有指物的名词时,用that引导.如:
He told us about the people and the citiesthathe had visited.
④先行词前有any,all,no,few,every,some,little,much,(the)very,(the)only,(the)last等词修饰时,用that引导.如:
This is the very coatthatI need.
⑤先行词为which时,为了避免重复,用that引导.如:
Which is the bookthatyou bought yesterday
⑥先行词在从句中作表语时,常用that引导.如:
Shanghai is no longer the citythatit used to be in the 1930s.
⑦当主句是There be...句型时,用that引导.
There are two tickets for the filmthatare for you two.
定语从句用法 6
when引导
关系副词when在非限制性定语从句中作时间状语，指代主句中表示时间的词语。
如：He will put off the picnic until May 1st, when he will be free.
他将把郊游推迟到5月1号，那时他将有空。
where引导
副词where在非限制性定语从句中作地点状语，指代主句中表示地点的词语。
如：They went to London，where they lived for six months.
他们去了伦敦，在那儿呆了六个月的时间。
as引导
as引出非限定性定语从句时，代替整个主句，对其进行说明但通常用于像as we all know, as it is known, as is known to all, as it is, as is said above, as always mentioned above, as is usual, as is often the case, as is reported in the newspaper等句式中。as在非限定性定语从句中作主语、表语或宾语，且引出的从句位置比较灵活，可位于句首或句末，也可置于主句中间。通常均由逗号将其与主句隔开。as有“正如……， 就像……”之意。
如：As is known to the United States, Mark Twain is a great American writer.
美国人都知道，马克·吐温是一位伟大的美国作家。（as在从句中作主语）
He forgot to bring his pen with him, as was often the case.
他忘了带笔，这是常事。（as在从句中作主语）
He is absorbed in work, as he often was.
他正在全神贯注地工作，他过去经常这样。（as在从句中作表语）
As we all know, the earth is round.
众所周知，地球是圆的。（as在从句中作宾语）
The two brothers were satisfied with this decision，as was agreed beforehand.
两兄弟对此决定都满意，这项决定在事前都已得到他们的同意。(as在从句中作主语)
Taiwan is，as you know，an inseparable part of China.
你知道，台湾是中国不可分割的一部分。(as在从句中作宾语)
“介词+关系代词”引导非限制性定语从句：在介词后引导非限制性定语从句。
难：句意相同
as it is known to all (that...) (as 做状语从句连词，是状语从句, 可以加that)
与 as is known to all (as做主语，是定语从句)
与 it is known to all that... (主语从句，it是形式主语)
即：As is widely known, the moon is closer to the us than the sun.(定从)
= That the moon is closer to the us than the sun is widely known.(主从)
= It is widely known that the moon is closer to the us than the sun.(主从)
As it is known to everyone, I thought you knew about it too.(状从)[1]
关系代词which有时并不代表主句中某一确定的词，而是概括整个主句的意思。介词的选择取决于它与先行词的搭配或与从句中谓语动词的搭配。
They were short of sticks to make frames for the climbing vines，without which the yield would be halved.
他们缺搭葡萄架的杆儿，没有它们产量会减少一半。
They thanked Tom，without whose support they would not have succeeded.
他们很感激Tom，没有他的支持他们是不会成功的'。
特殊结构
“名词/代词+of+which / whom”
It now has 20，000 hectares of land，more than two-thirds of which are under cultivation.
现在它拥有两万公顷土地，其中三分之二之多已经耕种。
Light is the fast thing in the world, the speed of which is 300000 kilometer per second.
光是世界上最快的东西，它的速度是每秒30万千米。
There are 30 chairs in the small hall, most of which are new.
大厅里有三十把椅子，绝大部分是新的。
The textile mill has over 8，000 workers and staff，eighty per cent of whom are women.
这家纺织厂有8千多职工，女职工占百分之八十。
定语从句用法 7
一、as引导定语从句与其它词连用
A．用于the same．．．as．．．结构中
This is the same sickle as I lost yesterday．这把镰刀和我昨天丢的那把一样。
We drove out of the town by the same road as we had entered by．我们沿着进城的同一道路开车出城。
This is the same material as is used in building the bridge．这和建那座桥所用的材料一样。
注意：在这一结构中，as有时可以由that代替。例如：
I live in the same district as ／that he lives in．我和他住在同一区。
但两者亦有区别：
1．当定语从句省略谓语部分时，要用as。例如：
She uses the same scent as you（do）／that you do．她用的香水和你的一样。
This book of his is the same as yours．他的这本书和你的那本一样。
2．在容易引起歧义时，慎用as和that。例如：
This is the same knife as I lost last week．
（一般理解为：这把刀和我上周丢的那把相似。也可理解为：这是我上周丢的那把刀。）
This is the same knife that I lost last week．这是我上周丢的那把刀。
3．that在现代英语中可作关系副词，而as则不可。例如：
I live in the same district that he lives．（不可用as。）
B．用于such．．．as．．．结构中
I never heard such stories as he tells．我从未听过像他讲的那种故事。
He was in such a fury as Ive never seen．他怒气之大，我从没见过。
Such women as knew Tom thought he was charming．认识汤姆的女人都认为他很有魅力。
注：有时such和as连在一起用。例如：
We had hoped to give you a chance such as nobody else ever had．我们本希望给你一次别人不曾有过的机会。
We are living in a new era such as has never existed before．我们生活在前所未有的新时代。
C．用于“so＋adj．＋a（n）＋n．（单数）＋as结构中
We witnessed so great a parade as nobody ever dreamt of in preliberation days．我们见到在解放前没有人曾经梦想过的一次盛大的。
Im not so strong a man as I was．我已不像从前一样健康了。
Hes never written again so good a book as his first one．他再也没写出像他的第一部那么好的书。
D．用于“as＋adj．＋n．＋as比较结构中
He is as learned a professor as works in the uni- versity．他是在这所大学工作的教授中最有学问的一个。
Some people have no doubt that their cat understands as many words as does a dog．许多人相信他们的猫跟狗懂的话一样多。
They are as fine women as ever walked．她们可以与任何卓越的女性媲美。
注：as．．．as．．．后面加上ever以加强语气，表示“不亚于任何……”，“不弱于……”，有最高级的意味。又如：
He is as brave a man as ever lived．他是世界上最勇敢的人。
二、as单独引导定语从句
A．as单独引导定语从句时，先行词可以是一个词，但更为常见的是：它的先行词是整个主句，有时也可以是一个短语。例如：
The two brothers were satisfied with this decision，as was agreed to beforehand两兄弟对此决定都很满意，这项决定事前已得到他们的同意。（先行词是decision）
She is late，as is often the case．她迟到了，这是经常的事。（先行词是整个主句）
He married her，as was natural．他和她结婚了，这是很自然的。（先行词是整个主句）
To shut your eyes to facts，as many of you do，is foolish．视而不见———你们好多人都是如此———是愚蠢的。（先行词是整个不定式短语）
B．as与which的区别
三、as引导定语从句的`用法比较
1.as作为关系代词可以引导限制性定语从句， 主要用于such...as，the same...as，so...as，as...as等结构中。例如：
（15）Let’s deal with such problems as concern us.
（16）The purpose of the conductor is to transmit the electrical energy with as little loss as is practicable.
（17）There are so many tickets available as are asked for.
（18）She wears the same watch as I do.（同一类）
（19）This is the same watch that I lost yesterday.（同一个）
在（15）句中，as指代such修饰的名词“problem”，并在从句中作主语成分；（16）句中，第二个as指代第一个as所修饰的“little loss”; （17） 句中as 指代so 修饰的名词“tickets”; 在（18） 句中，as 指代“the same” 修饰的名词“clothes”， 在从句中作宾语； 此情况下不能用that和which来代替as引导定语从句。
比 较：在（18）句中，as指代的先行词表同一类，强调种类一样。而在（19）中that指代的先行词虽然也被“the same”修饰，但是此时先行词表示同一个。
2.as和which引导非限制性定语从句比较。
as和which都可以引导非限制性定语从句，代替整个句子。但是具体使用方法是有区别的，请看下面的例句比较：
（20）As we known，Yao Ming is the most famous basketballplayer in China.
（21）The number of the people，as we had expected，was overthree thousand.
（22）The sun gives off light and warmth，which makes it possiblefor living creatures to grow.
（23）She is very beautiful，which makes others jealous.
（24）She is very kind to the children，which her husband seldomwas.
（25）He became a teacher，which I was not.
在（20）句中as放在了句首，所指代的内容就是后面的一句话“Yao Ming is the most famous basketball player in China”；（21）句as放在了句中，同样指代的是一句话“The numberof the people was over three thousand”。从这两个例句中我们发现as引导的从句和主句在内容上表示一致， 或者说从句的内容是顺着主句的意思说下来的，有“就像”、“正如”之意。再看一下（22）句和（23）句，which的位置放在了句中，并且which引导的非限制定语从句是主句造成的一种结果。比如我们在翻译（22）句时可以这样理解：太阳释放出光和热，这使生物生长成为可能；当然（23）句我们也可以这样翻译：她很漂亮，这使其他人和嫉妒。从（24）句和（25）句我们还可以看到which引导非限制性定语从句的另一种用法，即which引导的非限制定语从句与主句内容不一致， 或起对立、否定关系。
四、as引导状语从句的用法比较
1.as，when和while作为连词引导时间状语从句的比较。
若主、从句表示两个同时进行的持续性动作，且强调主句表示的动作延续到从句所指的整个时间， 通常要用while。但是，若主、从句表示的两个同时进行的动作含有“一边……一边”的意思，通常要用as。例如：
（26）Don’t talk while you’re eating.
（27）I kept silent while she was reading.
（28）She sang as she went along.
若从句是一个短暂性动作，而主句是一个持续性动作，一般用when。如果主、从句表示的是两个同时（或几乎同时）发生的短暂性动作，一般要用as。例如：
（29）When he came in，I was watching TV.
（30）It was raining hard when he arrived.
（31）I had guessed it just as you opened your mouth.
若要表示两个正在发展变化的情况， 相当于汉语的“随着”，一般用as。表示“每当……的时候”（暗示一种规律性），一般要用when。例如：
（32）Situations are getting better and better as time goes on.
（33）As it grew darker，it became colder.
（34）It’s warm when sun shines.
（35）He smiled when I praised him.
2.as，though 和although 作为连词引导让步状语从句的对比。
as引导让步从句时，句子必须倒装。常把被强调的作表语的形容词、名词及作状语的副词放句首，有时甚至把谓语动词放句首。though引导让步状语时，句子可以倒装（倒装方式和as一样）也可以不倒装。although引导让步状语时，只能用正常语序，不能倒装。下面我们看一下例句（36）—（39）：
（36）Poor as/though they are，they are very ambitious.
（37）Child as/though he is，his behavior seems mature.
（38）Hard as/though he worked，he didn’t pass the exam.
（39）Try hard as/though he will，he is not successful.
3.as，because，since 和for 作为连词引导原因状语从句比较。
because引导原因状语从句时语气最强， 常表示必然的因果关系，从句是全句的重心，它引导的从句一般放在主句的后面， 并且回答以why引起的特殊疑问句；as只说明一般的因果关系，语气比because弱，说明比较明显的原因，它引导的从句通常放在句首，常意为“由于”；since意为“既然”，表示对方已经知晓，无需加以说明的原因或事实（有时为天经地义的事实或格言、谚语等），语气比because稍弱，全句重点落在主句上；for是并列连词，它的语气最弱，常用来补充说明理由或提供一种解释，一般放在句中，强调“理由”。下面我们看一下例句再一次进行比较。
（40）He is absent today because he is ill.
（41）As everyone has arrived，we can set off now.
（42）I’ll do it for you since you are busy.
（43）We must leave now，for the film begins at seven.
4.as引导的方式状语从句用法。
as，（just） as...so...引导的方式状语从句通常位于主句后，但在（just） as...so...结构中位于句首，这时as从句带有比喻的含义，意思是“正如”、“就像”，多用于正式文体，例如：
（44）I shall do the exercises as you have been taught.
（45）As water is to fish，so air is to man.
（46）Just as we sweep our rooms，so we should sweep old ideas from our heads.
总之， 社会和英语语言的不断发展给英语语法的归纳和研究带来了很大的挑战，也给语言学习者带来了很多困难，但不管怎样，只要我们在学习过程中不断探索、勇往直前，一定能找到其中的规律， 帮助英语学习者消除英语学习中的重重障碍。
定语从句用法 8
WHOSE也可以引导定语从句，它相当于前面说的关系代词的所有格形式。
例：She has an uncle . His name is Peter.
=She has an uncle whose name is Peter.
I like that house . Its location is good to me.
=I like that house whose location is good to me.
"WHOSE"引导定语从句的三原则:
a. whose 前要有先行词
b. whose 后的`名词要做定语从句的主语或宾语
c. 否则whose前应有介词，且该介词也可移至定语从句的句尾
以上可知whose引导定语从句的用法和其他关系代词的用法相似。
例：I hate John,whose words are seldom true.(本句中，whose words 前有先行词John，且本身做定语从句的主语)
I hate John,whose words I have no trust.(错) (本句虽有先行词,但whose words 无法直接做trust的宾语，所以要稍加改正)
改正:I hate John,whose words I seldom trust in.(对)
附一：关系代词引导的定语从句
关系代词所代替的先行词是人或物的名词或代词，并在句中充当主语、宾语、定语等成分。关系代词在定语从句中作主语时，从句谓语动词的人称和数要和先行词保持一致。
1、who指人，在从句中做主语
The boys who are playing football are from Class One.
2、whom指人，在定语从句中充当宾语，常可省略。
Mr. Liu is the person (whom)you talked about on the bus.
【注意】关系代词whom在口语和非正式语体中常用who代替，可省略。
The man who/whom you met just now is my friend.
3、which指物，在定语从句中做主语或者宾语，做宾语时可省略
Football is a game which is liked by most boys.
4、that指人时，相当于who或者whom；指物时，相当于which。在定语从句中做主语或者宾语，做宾语时可省略。
The number of the people that/who come to visit the city each year rises one million.
5、whose通常指人，也可指物，在定语从句中做定语
He has a friend whose father is a doctor.
whose指物时，常用以下结构来代替：
The classroom whose door is broken will soon be repaired.
=The classroom of which the door is broken will soon be repaired.
Do you like the book whose cover is yellow?
=Do you like the book the color of which is yellow?
（注意：the + 名词 + of which/whom常考！）
附二：介词+关系代词whom/which引导的定语从句（重点）
关系代词在定语从句中做介词宾语时，从句常由介词+关系代词引导：
The school (that/which) he once studied in is very famous.
=The school in which he once studied is very famous.
【注意】
1、含有介词的动词短语一般不拆开使用，如：look for, look after, take care of等
（1）This is the watch which/that I am lookingfor.(T)
（2）This is the watch for which I amlooking. (F)
2、若介词放在关系代词前，关系代词指人时用whom，不可用who或者that；指物时用which，不能用that；关系代词是所有格时用whose
（1）The man with whom you talked is my friend.(T)
（2）The man who/that you talked with is my friend.(F)
3、“介词+关系代词”前可有some, any, none, both, all, neither, most,each, few等代词或者数词，构成some of which/whom等类似结构引导的定语从句。(重点：常考！)
（1）He loved his parents deeply, of whom both are very kind to him.
（2）In the basket there are quite many apples, some of which have gone bad.
（3）There are forty students in our class in all, most of whom are from big cities.
在特定语境中，可以用“介词+ whose/where”引导定语从句
The boss in whose department Ms King once worked is a kind man.
定语从句用法 9
1、引导限制性定语从句。在主句中常有the same, so或such与as相呼应, as在定语从句中可作主语、宾语、主语补足语等。as引出的定语从句带有比较意义，从句常常只写出比较部分，但as本身不可省略。例如：
He used such expressions as he could find in the texts. 他使用在课文中可以找到的那些词语。 They stayed for the night in the same room as they had once rented.他们在他们曾租用过的同一房间过夜。
注意：在the same…后也可用that引导定语从句，但含义有所不同。that引出的从句，指的`是与先行词同一的事物，而as引导的从句指的是与先行词同类的事物。例如： This is the same bag as I lost yesterday.这个包和我昨天丢失的包的样子是同样的。 This is the same bag that I lost yesterday.这就是我昨天丢失的那个包。
2、引导非限制性定语从句。带主句的全部或部分内容。常译为“正如-------”“就像------”等，定语从句可以置于主句句首、句中或句末。as后常接expect, know, report, say, see等动词的主、被动语态。例如：
As is known to everybody, the moon travels round the earth once every month.正如大家所知道的那样，月球每月绕着地球转一圈。
He wasn’t unconscious, as could be judged from his eyes.他并未失去知觉，这从他的眼神可以看出来。
注意：as, which引导非限制性定语从句的区别：
1）都可以代整个主句，相当于and this或and that.
2）as可放在句首，而which不能。
3）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；如果为行为动词，则从句中的关系代词只能用which. 例如：
It rained hard yesterday, which prevented me from going to the park.昨天下大雨，这使得我不能去公园。
定语从句用法 10
1. 不用that的情况
(1) 在引导非限定性定语从句时。
(错)The tree, that is four hundred years old, Is very famous here.
(2) 介词后不能用。
We depend on the land from which we get our food.
We depend on the land that/which we get our food from.
2. 只能用that作为定语从句的关系代词的情况
(1) 在there be 句型中，只用that，不用which。
(2) 在不定代词，如：anything, nothing, the one, all等作先行词时，只用that，不用which。
(3) 先行词有the only, the very,the same,the last,just修饰时，只用that。
(4) 先行词为序数词、数词、形容词最高级时，只用that,不能用which。.
(5) 先行词既有人，又有物时。
(6) 先行词指物，在主句中作表语时.
(7) 为了避免重复.
(8) 先行词是the way或the reason时，that可作关系副词，也可省略
(9) 主句的主语是疑问词who /which时
定语从句用法及精练
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，定语从句一般放在先行词的后面。
二、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，非限制性定语从句主句与从句之间有逗号分开，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。在从句中作主语或宾语，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，在句中作主语或宾语，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， 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， 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：
What’s 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，一般用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，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，在句中作时间状语。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，在句中作地点状语。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，起原因状语作用。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。
自我测试 / Test Yourself
I.单项填空。
1. -Do you know the man ______is talking with your father？
-Yes， he’s our headmaster.
A. he B. who C. which D. whom
2. Is this the river _____I can swim？
A. which B. in which C. that D. the one
3. This is the best hotel in the city _____I know.
A. where B. which C. that D. it
4. Can you lend me the dictionary ______the other day？
A. that you bought B. you bought it
C. that you bought it D. which you bought it
5. Anyone ______with what I said may put up you hands.
A. which agrees B. who agree
C. who agrees D. which agree
6. My watch is not the only thing ______ is missing.
A. that B. it C. which who
7. The man ______coat is black is waiting at the gate
A. who’s B. whose C. that of which.
8. The girl ______ is reading under the tree _____my sister.
A. which； is B. whom； was C. who； is D. who； was
9. I love places ______the people are really friendly.
A. that B. which C. where D. who
10. The world ______ is made up of matter.
A. in that we live B. on which we live
C. where we live in D. we live in
Ⅱ. 用适当的关系代词that， which， who， whom填空。
1. The first thing ______you must do is to have a meal.
2. April 1st is the day _____is called April Fool’s Day in the west.
3. The family _____had lost everything in a big fire got much help from their friends.
4. The house _____we live in is very old.
5. Didn’t you see the man ______I talked with just now？
参考答案：
I. 1-5BBCAC 6-10 ABCCD
Ⅱ. 1. that 2. which / that 3. who / that 4. that / which 5. who/ whom/ that
定语从句用法 11
(一)、 as作连词的用法:
as作连词，常用来连接主句和状语从句。
1.引导时间状语从句，作“当...的时候”解，有“随着...”之意，与while意义相近，强调两个动作同时发生;或某事一发生，另一事立即发生。eg：
He shouted aloud as her ran along.他一边往前跑，一边高声地呼喊。
I was startled as he opened the door.他一开门，我吓了一跳。
as作连词，相当于when。eg;
As a little boy (When he was a little boy)he began to learn to play piano.他小时候就开始学弹钢琴。
2.引导原因状语从句，作“因为，由于”解，与because的用法相近。eg;
I must stop writing now，as I have rather a lot of work to do.我必须停笔了，因为我还有许多工作要做。
3.引导方式状语从句或比较状语从句，作“正如，(如)像”解。例eg：
As in your country，we grow wheat in the north and rice in the south.正如(像)你们国家一样，我们在北方种小麦，在南方种大米。(方式状语从句)
When at Rome，do as Romans do.入乡随俗。(方式状语从句)
4.引导让步状语从句，作“虽然，尽管”解。这时从句常用倒装语序，即把从句中的表语、状语或动词原形放在as之前。eg;
Strange as it may seem，it is true.尽管这事看上去很奇怪，但却是真的。
Try as he might，Tom could not get out of the difficulties.不管怎样努力，汤姆还是摆脱不了困境。
1. 作“在-------期间，当----的时候”引导时间状语从句.注意与 when、 while的用法区别。
时间状语从句：as的用法
1.某事一发生，另一事立即发生
As the sun rose the frog dispersed 太阳一出来雾就消散。
They strolled into the garden as the music ceased. 音乐声一停，他们就走进花园。
2.在某事发生的过程中另一事发生
I heard the murmur of their voices as I crossed the hall.
我走过大厅的时候听到他们在嘀咕什么。(两个动作都是一般时态)
Just as he was speaking there was a loud explosion.
正当他在说话的时候，一声巨响。(从句用进行时态)
3. 两个动作同时发生
He smiled as he passed. 他路过的时候笑了一下。
As she sang, the tears ran down her cheeks. 她一边唱歌，眼泪一边从脸颊淌下。
Helen heard the story as she washed. 海伦一边洗衣服一边听故事。
He saw that she was smiling as she read. 他看到她一边看着书一边笑。
(两个都是延续性动作)
We get wiser as we get older. 我们随着年龄的增长而变得聪明起来。
(随着时间的.变化而变化)
①下列情形时,只用as, 而不用when或while。
1) 用于表示同一个人的两种动作交替进行,指一边----一边. 如:
The girl sings as she goes to school.
He looked behind occasionally as he went forward in the forest.
2)表示两个同步发生的动作或行为,意思是随着-----的发展.如:
As time went on / by, she became more and more beautiful .
As children get older, they become more and more interested in everything.
3)表示两个短暂行为或事情几乎同时发生.如:
I watched her as she read the book.
I thought of it just as you opened your mouth.
Just as the flying worm hit her face, she gave a loud cry.
4)接在名词后面表示某一个年龄段时.如:
As a young man, he was active in sports.
②when作"当……的时候"解,可以指较短的(一点)时间,也可指一段时间。如:
When I was at college, I could speak several foreign languages. When the clock struck twelve, I had slept for 2hours.
③while常表示一段较长的时间或一个过程,强调主句谓语动词与从句谓语动词同时发生。如:Work while you work. Play while you play.
2. As =Since 作"既然"、"由于"解,引导原因状语从句,常用来表示已为人们所知或显而易见的原因或理由。如:
As he’s been ill for ages, I will help him.
As / Since youre not feeling well, you may stay at home.
As he wasnt ready , we went without him.
3.As =in the way that作"像"、"按照……的方式"解,引导方式状语从句。如:
Do as I told you.
Remember, you must do everything as I do.
4. 用于as--- as或not / so/ as ---- as中, 前一个as是副词, 后一个as是连词, 引导比较状语从句。如:
They helped the old as much as possible.
I dont speak English so/ as well as she does.
5. 表示虽然, 尽管 等, 引导让步状语从句, 常用倒装语序, 模式为:
adj. /adv. / n.+as +主语+谓语+主句。如:
Young as he is, he knows much.
Tired as they were, they walked on.
6. 表示也------一样。
S he is a doctor, as was her husband.
(二)、 as作关系代词,引导定语从句,表示正如,这一点.如:
1. 引导限制性定语从句，用在“such...as”, “the same...as”，“as...as”等结构中，常译作“像...一样的人(或物)”，“凡是...的人(或物)”。
eg： He wished to be such a man as Lei Feng was.他曾希望做一个像雷锋那样的人。
My hometown is no longer the same as it was.我的家乡再也不像过去一样了。
2.引导非限制性定语从句，用来指代它前面的整个句子(即先行句)，意思是“这一点”。这个分句可以位于句首、句中或句末。
eg：As is well known，oceans cover more than 70% of the earth.
我们知道，海洋占地球面积的百分之七十以上。
He is very careful, as we all know.
As is well-known, belongs to China.
另外,当先行词被the same, such等词修饰时,常用as来引导定语从句。如:
Such a clever girl as she can learn anything quickly.
I was reading the same book as he bought yesterday.
(三)、as作介词的用法.
1. 作“如，像”解,表示好像。如:He dressed as a policeman.
They got united as one man.他们团结得像一个人一样。
2. 作“充当，作为”解,表示作为, 当作。如：I found a job as a guide.
As a writer，he was famous.作为作家，他是很有名的。
3.当某人是某身份时。如：As a child , she was sent to abroad.
4.as引导的介词短语大多用作状语,as译为"作为";少数情况可引起宾语补足语。如:
As a Party member, Ill take the lead in everything. (状语)
She works as a model. (状语)
She has me as one of her best friends.(引起宾语补足语)
(四)、作副词的用法
as作副词，表示程度，意为“同样地”。在“as...as...”，“not as...as...”结构中的第一个as是副词，作“和/与...(不)一样”解。
e.g. Jack is as tall as his father.杰克和他的父亲一样高。
He doesnt speak English as/so fluently as you.他的英语说得不如你流利
1 表示与------等同。
如：This dress is twice as expensive as that one.
2 像，如等。
如：As before, he remained unmoved.
五)含as的固定词组的用法
1. as soon as作“一…就”解，引导时间状语从句。
eg：As soon as I get to Beijing，Ill write to you.我一到北京，就给你写信。
2.as/so long as作“只要”解，
e.g. As/So long as you study hard，youll make progress.只要你努力，你就会取得进步。
2. as if/though常用来引导方式状语从句，作“好像，仿佛”解。如果从句中讲的是非真实情况，则用虚拟语气。
e.g. She loves the child as if/though he were her own.
她爱这个孩子如同爱自己的孩子。
3. As if/though也可用来引导表语从句，常用在“It appears/looks/seems...+as if/though”句型结构中。
e.g. It appears as if/though it is going to clear up.看起来天要晴了。
It seems as if/though he knew nothing about it.他好像对此事一无所知。4.as to作“关于，至于”解。
e.g. There is no doubt as to his honesty.他的诚实是无可置疑的。
5.as much/many as作“多达...”，“达到...之多”解。
e.g：He can earn as much as 5000 dollars a month.他每月能挣5000美元。
6.so/as far as I know作“就我所知”解，在句中作插入语。
eg： As/So far as I know，he will come here next Monday.
据我所知，他将于下星期一到这里来。
7.as a result，as a result of表示“由于...的结果”。
e.g. She died as a direct result of the accident.她的死是那次事故的直接结果。
8，as well为“也，还”之意。
e.g. Come early，and bring your brother as well.早点来，把你的弟弟也带来。
9.so as to，so...as to若跟动词原形，表示目的或结果。
eg：He studied hard so as to pass the exam.他努力学习以便通过考试。(表示目的)
定语从句用法 12
that的用法大全：
that的用法1：that用作指示代词的意思是“那,那个”。可指前面提到的那件事,也可指在空间或时间上较另一事物远的事物或人,还可指要表明的`或要提及的事物、想法等。
that的用法2：that用作关系代词时,指人或事物,同时又在从句中充当句子成分。that偶尔也可引导非限制性定语从句。
that的用法3：that还常用以代替who, whom, which,但that...which中的that用做关系代词的先行词。
that的用法4：that用作关系代词时在下列情况下可以省略:①引导限制性定语从句在从句中用作宾语时; ②用在there be结构前作主语时; ③用作表语时; ④在定语从句与先行词之间有插入语时; ⑤在先行词way, reason, distance, place, office等作方式状语、原因状语或地点状语时。
that的用法5：that用作连词时可引导主语从句、宾语从句、表语从句、同位语从句和状语从句。
that的用法6：that还常引导间接引语或形容词后面的从句。
that的用法7：that在以it作形式主语的句子中或引导宾语从句、状语从句时常可省略。
that的用法8：that也可用于表示愿望或遗憾。
that的常用短语：
atthat
for allthat
inthat
thatis (to say)
thatsthat
that的用法例句：
1. A miracle is somethingthatseems impossible but happens anyway.
奇迹就是看似不可能，却发生了。
2. If you wait, allthathappens isthatyou get older.
如果你等待，发生的只有变老。
3. When life gets hard and you want to give up, rememberthatlife is full of ups and downs, and without the downs, the ups would mean nothing.
当生活很艰难，你想要放弃的时候，请记住，生活充满了起起落落，如果没有低谷，那站在高处也失去了意义。
4. Eventually, youll learn to crythaton the inside.
终有一天，你会学会让泪往心里流。
5. Success is not final, failure is not fatal: it is the courage to continue thatcounts.--Winston Churchill
成功不是终点，失败也并非末日，最重要的是继续前进的勇气。
6. Its not about making the amazing saves. Its the little things and small thingsthat made great gatekeepers great.
伟大的门将不是靠神奇的扑救成就，而是靠注重小事和细节成功。(Tim Howard美国国家队门将)
7. The turning point in the process of growing up is when you discover the core of strength within youthatsurvives all hurt.
当你从内心深处找到一种可以忍受一切痛苦的坚强力量时，你的成长历程就会出现飞跃。
8. It was just thenthatI chanced to look round.
就在那时，我恰好环顾了下四周。
9. I dont want any more ofthatheavy stuff.
我再也不想碰那种麻烦事了。
10. It was the uncommittedthatLabour needed to reach.
工党需要拉拢的是未表态者。
11. The vehiclethatpermitted both communication and acceptability was social revolution.
既能实现交流又能被广为接受的手段就是社会革命。
12. We all knowthatfats spoil by becoming rancid.
我们都知道油脂变质后会发臭。
13. He admittedthatthe government was in "a dreadful hole".
他承认政府目前“处境极为尴尬”。
14. She probably sensedthatI wasnttelling her the whole story.
她可能意识到了我并没有对她全盘托出。
15. He plays some passages so slowlythatthey become lugubrious.
有些段落他演奏得异常徐缓，听上去有些忧伤。
定语从句用法 13
限定性定语从句对被修饰的先行词有限定制约作用，使该词的含义更具体，更明确。
限定性定语从句的用法
在引导限定性定语从句时，that有时相当于in which,at which,for which或on which
（1）Attitudes towards daydreaming are changing in much the same way that(in which) attitudes towards night dreaming have changed. 人们对白日做梦的态度正在改变，这与人们对夜间做梦的看法的变化有非常相似之处。
（2）I like the music for the very reason that(for which) he dislike it. 我出于某种原因喜欢这种音乐，而他恰恰与我相反。
（3）We arrived the day that(on which) they left. 刚好我们到的那天他们走了。
在限定性定语从句中，当关系代词在从句中担任动词宾语时，关系代词可省略。
（1）The book (that/ which) I am reading is very interesting. 我在读的书很有趣。
（2）Is there anything (that) you wanted? 想要什么东西吗?
限制性定语从句与非限制性定语从句用法区别：
一、 句法的`功能、表现形式不同
定语从句分为限制性和非限制性两种。限制性定语从句不可缺少先行词，去掉它主句意思往往就不明确了，它与主句之间通常不用逗号分开；非限制性定语从句是对先行词的附加说明，去掉它也不会影响主句的意思。如：
Do you know the professor who is speaking at the meeting? （限制性定语从句）
English is an important subject, which every student should study well. （非限制性定语从句）
二、 先行词不尽相同
限制性定语从句的先行词往往是某一个词，但非限制性定语从句的先行词可以是一个词，也可以是句子的一部分，甚至是整个主句，此时非限制性定语从句一般由which或as引导，as引导非限制性定语从句常用在as is said / known / expected / mentioned / reported / announced等结构中。如：
He has passed the college entrance examination, which makes his parents quite happy.
As is known to everybody, the moon travels round the earth once every month.
三、 关系词的使用情况有所不同
1． that 不可引导非限制性定语从句。如：
Her father gave her a computer for her birthday，which pleased her a lot.
2． why 不用在非限制性定语从句中，需用for which代替。如：
I told them the reason, for which I didnt attend the party last week.
3． 关系代词替代情况不同
关系代词 whom 在限制性定语从句中作宾语时可用 who 代替 whom, 但 whom 在非限制性定语从句中作宾语时不可用 who代替。如：
This is the girl whom (who) I have been in love with for six years.
The young man had a new girl friend, whom he wanted to show all his love for.
4． 关系代词省略情况不同
关系代词在限制性定语从句中作宾语时可以省略；非限制性定语从句的所有关系代词均不可省略。如：
She is the new student (whom / who / that) I want to introduce to you.
All the books there, which have beautiful pictures in them, were written by him.
四、 下列情形用非限制性定语从句
1. 当“不定数量词 (如some, several) ／ 数词 ＋ of which ／ whom”表示“整体 (which ／ whom)中的一部分”的概念时。如：
We saw many animals in the zoo, some of which are tigers．
There are fifteen new players in our team, two of whom come from Canada.
2. 当先行词为专有名词或被物主代词和指示代词修饰时，其后的定语从句通常是非限制性的。如：
My house, which I bought last year, has got a lovely garden.
Qingdao, where I have been three times, is an attractive city to foreigners.
定语从句用法 14
定语从句why的用法
关系副词why在定语从句中也是用作状语，表示原因;why引导定语从句时，其先行词只有一个，那就是the reason;在许多情况下why也可以理解为for which。如：
These are the reasons why we do it. 这些就是我们这样做的理由。
句中的why we do it为修饰the reason的定语从句，关系副词why在此相当于for which。
Do you know the reason why she doesn’t like me? 你知道她不喜欢我的原因吗?
句中的why she doesn’t like me为修饰the reason的定语从句，关系副词why在此相当于for which。
why是一个比较特殊的关系副词，它引导定语从句时，除可换成for which外，有时也可换成that，甚至省略。如：
他失去工作的主要原因是他喝酒。
正：The main reason why he lost his job was that he drank.
正：The main reason for which he lost his job was that he drank.
正：The main reason that he lost his job was that he drank.
正：The main reason he lost his job was that he drank.
定语从句when和where的用法
1. when的用法
关系副词when在定语从句中用作状语，表示时间，用以修饰表示时间的先行词;在许多情况下可以理解为“介词+which”的意思(which的意思与先行词所表示的意思等价)，其中的“介词”通常应根据先行词的含与搭配来确定。如：
1988 was the year when he was born. 1988是他的出生年。
句中的when he was born为修饰the year的定语从句，关系副词when在此相当于in which。表示在某一年，英语习惯上用介词in，如in 1988, in 2008等，所以此处用in which。
I’ll never forget the day when I first met you. 我永远不会忘记第一次见你的那天。
句中的when I first met you为修饰the day的定语从句，关系副词when在此相当于on which。表示在某一天，英语习惯上用介词on，如on that day, on Friday等，所以此处用on which。
Don’t forget the time when the wedding will start. 不要忘记婚礼开始的时间。
句中的when the wedding will start为修饰the time的定语从句，关系副词when在此相当于at which。表示在某一时刻，英语习惯上用介词at，如at that time, at the moment等，所以此处用at which。
2. where的用法
关系副词where在定语从句中也是用作状语，表示地点，用以修饰表示地点的先行词;在许多情况下也可以理解为“介词+which”的意思(which的意思与先行词所表示的意思等价)，其中的“介词”通常应根据先行词的含与搭配来确定。如：
What is the name of the town where you live? 你住的那个城市叫什么名字?
句中的where you live为修饰the town的定语从句，关系副词where在此相当于in which。表示在住在某城市，英语习惯上说明live in a city，所以此处用at which。
This cross marks the spot where she died. 这个十字符号标明她死去的地点。
句中的where she died为修饰the spot的.定语从句，关系副词where在此相当于at which。表示在在某一地点，英语习惯上说明at a spot，所以此处用at which。
定语从句主要关系代词的用法
1. that的用法
that是所有关系代词中最常用的，它既可指人也可指物，既可用作主语也可用作宾语。如：
This is the photo (that) I took. 这就是我拍的照片。
引导定语从句的关系代词that在此指事，且在定语从句中用作宾语，故可以省略。
They live in a house that was built 200 years ago. 他们住在一座两百年前盖的房子里。
引导定语从句的关系代词that在此指物，且在定语从句中用作主语，故不可以省略。
The man that I saw told me to come here. 我见到的人让我到这里来。
引导定语从句的关系代词that在此指人，且在定语从句中用作宾语，故可以省略。
2. who / whom的用法
关系代词who和whom均只能指人，不能指物;从理论上说，who是主格，在定语从句中用作主语;whom是宾格，在定语从句中用作宾语。但在实际运用中，除非是直接用作介词后作宾语，否则凡是用宾格whom的地方。如：
I met someone who said he knew you. 我碰到一个人，他说认识你。
引导定语从句的关系代词who在此指人，且在定语从句中用作主语，故不可以省略。
She is the girl (who, whom) you saw in school. 她就是你在学校见到的那个女孩。
关系代词在定语从句中用作宾语，从理论上说应用whom，但也可以用who;由于是用作主语，所以它们也可以省略。
注意，如果关系代词是直接用作介词后作宾语，不可以用who来代替whom。如：
The girl to whom I spoke is my cousin. 我和她谈话的那个姑娘是我表妹。
句中的whom直接用在介词to的后面作宾语，故不可省略。
3. whose的用法
不要以为关系代词whose只用于指人，其实它也可以用于指事物;whose在定语从句中主要用作定语。如：
He is the man whose car was stolen. 他就是汽车被窃的人。
It was an island whose name I have forgotten. 这是一座岛，名字我忘了。
第一句中的关系代词whose指人，第二句中的关系代词whose 指物。
限制性和非限制性定语从句
根据从句与主句的关系是否紧密来区分，定语从句可分为限制性定语从句和非限制性定语从句两大类。
所谓限制性定语从句，它的作用是对先行词起修饰、限制或确定的作用，若去掉，先行词的意思就不明确，它是不可缺少的一部分，它与先行词的关系密不可分，不可用逗号将其分开。
而非限制性定语从句的作用则只是对先行词起补充说明作用，它是可有可无的，与先行词关系松散，通常用逗号将其分开。因此，有无逗号通常是区分限制性定语从句和非限制性定语从句的重要标志。
从所使用的关系词来看，在限制性定语从句中，that可以代替who, whom和which等，但在非限制性定语从句中不能用that。如：
He changed his mind, which made me very angry. 他改变了主意，这使我很生气。
句中的which引导非限制性定语从句，不可换成that。
Then he met Mary, who invited him to a party. 后来他遇到玛丽，玛丽邀请他去参加晚会。
句中的who引导非限制性定语从句，不可换成that。
另外，关系副词when和where既可引导限制性定语从句，也可引导非限制性定语从句;但关系副词why则只能引导限制性定语从句，不能引导非限制性定语从句。
We’ll put off the picnic until next week, when the weather may be better. 我们将把野餐推迟到下星期，那时天气可能会好一点。
Barbary was working in Aubury, where she went daily in a bus. 巴巴拉在奥伯里工作，每天得坐公共汽车去上班。
以上两句中的关系副词when和where均引导非限制性定语从句。
- as定语从句用法总结参考 推荐度：
- 相关推荐
【定语从句用法】相关文章：
定语从句as的用法总结09-14
定语从句where用法08-11
as定语从句用法总结参考02-26
which定语从句的用法总结07-23
that引导的定语从句的用法总结05-01
定语从句that的用法例句05-24
定语从句why的用法例句06-30
定语从句中where的用法总结08-22
非限制性定语从句的用法07-16