关系代词as的用法
1. 用于引导限制性定语从句，主要与such, as, the same连用，其意为“像??的”“凡是??的”“??一类的人(物)”。如：
He’s not such a fool as he looks. 他并不像看上去的那样愚蠢。
He is not such a man as would leave his work half done. 他并不是一个做事半途而废的人。 You must show my wife the same respect as you show me. 你必须对我妻子表现出与对我同样的敬重。
He smokes as expensive a cigarette as he can afford. 他抽一种他买得起的最贵的烟。 2. 用于引导非限制性定语从句，根据情况可位于主句之前或之后，有时也可插在主句中间，其意为“这件事”“这一点”。如(www.yygrammar.com)：
He is late, as is often the case. 他迟到了，这是经常的事。
As is usual with children, they soon got tired. 孩子们一贯如此, 他们很快就厌倦了。 David, as you know, has not been well lately. 大卫最近身体不太好，这你是知道的。
关系代词 as与which的用法区别
1. 引导限制性定语从句时，在such, as, the same后只能用as，其他情况用which。如： I never heard such stories as he tells. 我从未听过他讲那样的故事。(不可用which) It’s the same story as I heard from her yesterday. 这故事跟我昨天从她那儿听到的一样。(不可用which)
2. 引导非限制性定语从句时，有时两者可互换。如：
I live a long way from work, as [which] you know. 我住得离工作单位很远，这你是知道的。
但在，在以下情况引导非限制性定语从句时，两者不可换用： ①当从句位于主句前面时，只用as。如：
As you will find out, I will never let you down. 你将会发现，我决不会让你失望。 As is known to everybody, the moon travels round the earth once every month. 月球每月绕地球转一周，这是每个人都清楚的。
②as引导的非限制性定语从句应与主句在意义上和谐一致，而which则无此限制。如： She married him, as [which] was natural. 她嫁给了他，那是自然的事。
She married him, which was disgraceful. 她嫁给了他，那是很丢人的。(不用as) ③as引导非限制性定语从句时，先行词通常不能是主句中某个具体的词，而应是整个句子、整个短语或某个短语推断出来的概念，而which则无此限制。如：
I once lived in Guangzhou, which is the largest city in south China. 我曾住在广州，那是中国南方最大的城市。(不用as)
④当as引导非限制性定语从句作主语时，其谓语通常应是连系动词，而不宜是其他动词，而which则无此限制。如(www.yygrammar.com)：
She has married again, as [which] seemed natural. 她又结婚了，这似乎很正常。 She has married again, which delighted us. 她又结婚了，这使我们很高兴。(不用as)
关系代词who与that的用法区别
两者都可用作关系代词指人，有时可互换，但以下几点需注意：
1. 在 all, nobody, no one, somebody, someone, anybody 等词之后两者都可用，但以用 that 较普通。如：
All that [who] heard him were delighted. 所有听了他讲话的人都很高兴。 Have you met anybody that [who] has been to Paris? 你遇见过到过巴黎的人吗? 2. 在序数词、形容词最高级以及 the only, the same, the very 等之后两者都可用，但以用 that 较普通。如：
Newton was one of the greatest men that [who] ever lived. 牛顿是世界上最伟大的人物之一。
He is the only one among us that [who] knows Russian. 他是我们中间唯一懂俄语的人。 3. 引导非限制性定语从句时，通常只用 who。如：
Mrs Smith, who has a lot of teaching experience, will be joining us next term. 史密斯夫人很有教学经验，她下个学期将来与我们一道工作。
4. 但是在下列情况，通常只用 that(www.yygrammar.com)： ①当先行词是一个既指人又指物的并列词组时。如：
I made a speech on the men and things that I had seen abroad. 我就我在国外所见到的人和事作了报告。
②当先行词是 who 时(为避免重复)。如：
Who that has sympathy can laugh on that occasion? 有同情心的人谁会在那个时候发笑呢? ③当关系代词在定语从句中作表语时(可省略)。如:
Tom is not the boy (that) he was. 汤姆这孩子已不是以前那个汤姆了。
关系副词用法小归纳
■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。
■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。表示住在某城市，英语习惯上说 live in a city，所以此处用 in 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。表示在某一地点，英语习惯上说 at a spot，所以此处用 at which。
■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.(www.yygrammar.com)
whose引导定语从句只能指人吗
本站特约作者 刘 亚
大家知道，关系代词who只用于指人，不用于指物。我们是不是可以推出，关系代词whose也只用于指人不用于指物呢？不能！事实上，用作关系代词的whose既可用于指人，也可用于指物，同时还可以指动物，它在定语从句中用作定语，修饰其后的名词。
一、指人的用法
The boys whose names were called stood up. 叫到名字的男孩们站了起来。
The film is about a spy whose wife betrays him. 电影讲的是一个被他妻子出卖的间谍。 He was an officer whose career meant everything to him. 他是一名军旅生涯对他来说就是一切的军官。
The girl whose work got the prize is the youngest in her class. 作品获奖的那个女孩是她班上年纪最小的。
除引导限制性定语从句外，也可引导非限制性定语从句。如：
Chopin, whose works are world famous, composed some of his music in this room. 肖邦的作品是世界知名的，有些乐曲就是在这个房间里谱写的。
We went with Peter, whose car broke down before we were halfway there. 我们和彼得一起去的，但是还没走到半路他的车子就抛了锚。
Ann, whose children are at school all day, is trying to get a job. 安的孩子们整天都在学校，所以她在想办法找份工作。
二、指物的用法
The house whose windows are broken is unoccupied. 那个窗户破了的房子没人住。 I’d like a room whose window looks out over the sea. 我想要一个窗户面临大海的房间。 除引导限制性定语从句外，也可引导非限制性定语从句。如：
His house, whose windows were all broken, was a depressing sight. 他的房子窗户无一完好，一派令人心酸的景象。
三、指动物的用法
Wolves are highly social animals whose success depends upon cooperation. 狼是高度群体化的动物，它们的成功依赖于合作。
除引导限制性定语从句外，也可引导非限制性定语从句。如：
My bitch, whose temper is very uncertain, often bites the judges at dog shows. 我的母狗脾气不稳定，常常在狗展上咬裁判。
【做题小技巧】
对于考查关系代词whose的考题，掌握以下两点非常有用：
1. 它在定语从句中通常是用作定语，所以其后通常应有被修饰的名词。
2. which有时也可用作定语，但与whose在语义上有很大区别：which在语义上相当于this或that，而whose在语义上则相当于one’s。比较并体会：
It was an English novel whose name I have forgotten. 那是一本英语小说，书名我忘了。 My father may have to go into hospital, in which case he won’t be going on holiday. 我父亲可能需要住院，如果那样他就不去度假了。
【小练一下】
01. Cohen, ______ contract expires next week, is likely to move to play for a European club. A. his B. whose C. of him D. with whom 02. There was a picture in the paper of a man ______ leg had been blown off. A. which B. of which C. that D. whose