高中英语-定语从句知识点和练习(含答案)

合集下载

高中英语---定语从句特殊情况专项讲解及练习(有答案)

定语从句一、定语从句中只能用that 引导的情况1．当先行词为all, much, little, something, everything, anything, nothing, none, few, the one 等词时。

Everything that he said was true.2.当先行词被the very（恰恰，正好）, the only，any，few，little，no，all修饰时。

This is the very grammar book (that) I want to buy.The only thing that is constant is change.There was little that we could do to help her.3．当先行词是形容词最高级或被形容词最高级修饰时。

This is the best that has been used against pollution.This is the most interesting film that I've ever seen.4. 当先行词是序数词或被序数词修饰时。

The first place that they visited in London was the Big Ben.What is the first American film that you have seen?5．当主句的主语是疑问词who或which时。

Who that has common sense will believe such nonsense?Which is the T-shirt that fits me most?6．当先行词既有人又有物时。

Do you know the things and persons that they are talking about?7．先行词在定语从句中做表语,而关系代词在从句中也做表语时。

高考英语必考语法--定语从句详细讲解(附练习题及答案)

高考英语语法定语从句 attributive clause◆概念(1) 定语从句：在主从复合句中用作定语(修饰某一名词或代词)的从句叫定语从句，一般紧接在先行词(antecedent)后面。

(2) 先行词：被__________修饰的成份。

先行词可以为一个词，短语，或整个主句。

(3)引导定语从句的词叫关系词关系代词____, ______, ______, ______, _____, _______关系副词 _____, ______, ______ 在从句中作某个句子成份（可以做主语，宾语，定语，状语）第一找出先行词；第二看先行词在定语从句中的语法功能（做主语、宾语、定语或状语）；第三选择合适的关系词。

考点一：关系代词引导的定语从句1.who ,whom 和whose 引导的定语从句(1)who或whom均可指代人，但who在从句中作主语或宾语，做宾语时不可以出现在介词后；whom在从句中作宾语；两者在引导限制性定语从句时可用that 替换。

作主语时，who/that不可省略；作宾语时，whom/who/that可以省略。

◆ I’ve become good friends with several of the students in my school _________I met in the English speech contest last year.◆ I have many friends to _________ I’m going to send post cards.◆ The person I want to talk about with is Tu Youyou, the one ______ won theNobel Prize in Physiology or Medicine in 2015.(2)whose表所属关系，一般指人，也可指物，在从句中作定语。

(英语)英语定语从句解题技巧及练习题(含答案)

【点睛】
做定语从句时，可先将先行词还原到句中。其次选择关系词，要先看先行词指人、指物还是既指人又指物。二要看从句中做何种成分，从而做出正确的判断。
7．My mother doesn't like stories _____have sad endings.
A．thatB．whoC．whereD．those
（英语）英语定语从句解题技巧及练习题(含答案)
一、定语从句
1．The Palace Museum is the best placeI’ve ever visited.
A．whoB．thatC．whereD．what
【答案】B
【解析】
试题分析：句意：故宫博物院是我曾经参观过最好的地方。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，先行词前有序数词或被形容词最高级修饰时，用that而不用which。本句中先行词是the best place，此先行词为下文定语从句的逻辑宾语，指物，先行词前有最高级修饰，故用that引导此句的定语从句。选B。
【答案】A
【解析】
【详解】
句意：我妈妈不喜欢有悲伤的结局的故事。
根据句子结构可知这里考查定语从句的引导词，先排除D；先行词是stories，指物，排除B；且定语从句中缺少主语，应用关系代词，排除C，故选：A。
8．﹣Look！This is the photoI took in Beijing World Gardening Expo（世界园艺博览会）in 2019．
【答案】C
【解析】
【详解】
句意：出席上海合作组织青岛峰会的8国领导人受到中国人民的欢迎。考查关系代词辨析。what不是关系词，可排除。whom和who都用于先行词是人时，但whom用作宾语，who用作主语或宾语；which用于先行词是物时。本句先行词The leaders是人，可排除which；关系词在从句中做主语，可排除whom。根据句意结构和语境，可知选C。

高中英语定语从句讲解及练习题(含答案)

定语从句讲解1．基本介绍❶功能：相当于adj,修饰名词或代词，在句中作定语。

❷位置：被修饰词之后❸先行词：被定语从句修饰的词❹关系词：连接先行词与从句的词称为关系词。

❺确定关系词的步骤：先看先行词，指的是什么；看关系词在充当的成份。

关系词用法成份例句that 人、物主、宾Is he the man that wants to see you?who 人主Is he the man who wants to see you?whom谁+N 主、宾He is the man whom I saw yesterday?whose 谁的+N 定语Please pass me the book whose cover is green.which 哪个、物主、宾This is the house which we bought last month.关系代词as 正主、宾、表As we all know,smoking is harmful to one’s health.when 什么时候There are occasions when(on which)are must yield.where 地点哪里Beijing is the place where(in which) I was born.关系副词why 表原因介词+whichIs this the reason why(for which) he refused ouroffer?二．特殊用法情况用法先行词只用that,不用which,指物宜用which，不用thatas/which的区别❶先行词是序数词或形容词最高级时关系词前有介词无先行词的定语从句中用as/which引导❷先行词被all/every/no/some/any/little/much/the only/the very/few等词修饰时引导非限制性定语（有逗号隔开的句子）从句❸先行词既有人又有物时先行词本身是that ❹先行词在主句中做表语as:“正如.....一样”，可置句首。

(英语)必备英语定语从句技巧全解及练习题(含答案)含解析

（英语）必备英语定语从句技巧全解及练习题(含答案)含解析一、定语从句1．The Palace Museum is the best place I’ve ever visited.A．who B．that C．where D．what【答案】B【解析】试题分析：句意：故宫博物院是我曾经参观过最好的地方。

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，先行词前有序数词或被形容词最高级修饰时，用that而不用which。

本句中先行词是the best place，此先行词为下文定语从句的逻辑宾语，指物，先行词前有最高级修饰，故用that引导此句的定语从句。

选B。

考点：考查定语从句。

2．---How do you like the Sun Island？Is it worth visiting?---Sure. It’s one of the best places I have ever been to.A．which B．that C．who【答案】B【解析】【详解】句意：----你觉得太阳岛怎么样？值得一游吗？----当然。

这是我去过的最好的地方之一。

考查定语从句引导词。

本句先行词places是物，引导词在定语从句中作宾语，可知用that或which引导此定语从句，但先行词有最高级修饰时，只能用that引导此定语从句。

故选B。

【点睛】定语从句是用作定语的从句。

被定语从句所修饰的名词或代词叫先行词。

定语从句紧跟先行词（名词或代词）之后。

引导定语从句的词叫引导词，引导词分为关系代词（that/who/whom/which/whose）和关系副词（when/where/why）。

引导词连接先行词和定语从句，在定语从句中充当一定的成分（关系代词充当主语或宾语，关系副词充当状语）。

先行词是物时，用that或which引导定语从句；当先行词是人时，用who或that引导定语从句。

（一）、当先行词是物时，只用that的情况：1.当先行词被序数词或形容词的最高级修饰时。

高中英语定语从句语法精讲练习(带答案)

高中英语语法讲解——定语从句(名师精讲必考语法知识点+实战训练，建议下载练习)一、先行词、关系代词和关系副词1．先行词(antecedent)就是被定语从句所修饰的名词。

在英语中，定语从句跟在被修饰词之后，所以被修饰词就是“先行”的词。

eg. The lovely girl often helps the old lady.She lives next door to our school.→The lovely girl who lives next door to our school often helps the old lady.→The lovely girl often helps the old lady who lives next door to our school.The lovely girl often helps the old lady.You met her at school yesterday.→The lovely girl (whom)you met at school yesterday often helps the old lady.→The lovely girl often helps the old lady (whom) you met at school yesterday.2．连接定语从句，要用关系代词(relative pronoun)和关系副词(relative adverb)。

关系代词和关系副词与连接词不完全相同，因为它们除了连接主句和定语从句，还在定语从句中代替一定的成分。

eg. The book which I bought yesterday is very interesting.← The book is very interesting. I bought the book yesterday.I have visited the house where Andersen wrote The Emperor’s New Clothes.←I have visited the house. Andersen wrote The Emperor’s New C lothes in the house.二、关系代词1．who的先行词是“人”，在从句中代替主语。

必备英语定语从句技巧全解及练习题(含答案)

必备英语定语从句技巧全解及练习题( 含答案 )一、定语从句1．I really like the family photo ________ we took on my grandpa th birthday.’ s 80 A． who B． that C． what D． whose【答案】B【分析】【详解】句意：我真的很喜爱爷爷80 岁诞辰时拍的全家福。

此题考察定语从句。

A. who指代人； B.that 既能够指人又能够指物；题干可知本句中的先行词是C. what 不可以指引定语从句；D. whose 指代某人 / 物的。

依据photo ，指物，所以 B 选项 that 切合题意，故答案选B。

2．All the children like the teachers ________ can understand them.A． what B． which C． who D． whose【答案】 C【分析】【详解】句意：全部的孩子都喜爱能理解他们的老师。

本句是一个定语从句，先行词 teachers 是人，并且关系词在定语从句中作主语，故用关系代词 who 指引此定语从句，应选 C。

3．—Have you seen my watch anywhere, Lucy?—Is it the one your uncle bought for you in Hong Kong?A． who B． what C． that【答案】 CD． when【分析】试题剖析：句意：－露西，你在哪儿看到我的表了吗？－是你叔叔在香港给你买的那一块吗？后句是一个带有定语从句的复合句，先行词the one 指事物“表”，关系词用that 。

应选C。

考点：考察连词辨析。

4．This is the most beautiful picture __________ I have ever seen.A． that B． which C． what【答案】 AD． who【分析】句意：这是我见过的最美丽的画。

高中英语语法基础 ——定语从句知识点总结归纳讲解(附同步练习)(有答案)

高中英语语法基础——定语从句知识点归纳讲解（附同步练习）★先行词：被定语从句修饰的名词或代词叫先行词。

通常情况下，引导词前面的名词即为从句的先行词。

★关系词：引导定语从句的词叫关系词。

也可以称作引导词。

①关系代词：who，whom，which，that，whose，as，在从句内作主语、宾语等名词性成分。

②关系副词：when，where，why在从句内作状语。

（一）. 使用who、whom、which、that的定语从句1. whoThis is the boy who plays basketball very well.This is the teacher who is teaching us English.▲who 指人, 在从句中作主语。

2. whomThis is the boy (whom) I often help.The man is our headmaster (whom) you met just now.I met the girl (whom) you often praise.▲whom 指人,在从句中作宾语, 可省略。

3. whichThis is the farm which keeps many cows.This is the farm (which ) I visit every year.▲which 指事物, 在从句中作主语或宾语,作宾语时可省略。

4. that以上三种情况均可用that。

指人或指物，可作主语和宾语，作宾语时可省略。

（二）. 使用whose的定语从句Do you know the girl whose father is mayor.I used to work in an office whose window faces north.I work in a school whose students are excellent.▲whose 指人或物的所属关系，表示“某人的”或“某物的”。

(精校版)高中英语定语从句讲解及练习题(含答案)

(直打版)高中英语定语从句讲解及练习题(含答案)(word版可编辑修改)编辑整理：尊敬的读者朋友们：这里是精品文档编辑中心，本文档内容是由我和我的同事精心编辑整理后发布的，发布之前我们对文中内容进行仔细校对，但是难免会有疏漏的地方，但是任然希望（(直打版)高中英语定语从句讲解及练习题(含答案)(word版可编辑修改)）的内容能够给您的工作和学习带来便利。

同时也真诚的希望收到您的建议和反馈，这将是我们进步的源泉，前进的动力。

本文可编辑可修改，如果觉得对您有帮助请收藏以便随时查阅，最后祝您生活愉快业绩进步，以下为(直打版)高中英语定语从句讲解及练习题(含答案)(word版可编辑修改)的全部内容。

定语从句讲解一．基本介绍❶功能：相当于adj，修饰名词或代词，在句中作定语。

❷位置：被修饰词之后❸先行词：被定语从句修饰的词关系词用法成份例句that人、物主、宾Is he the man that wants to see you？who人主Is he the man who wants to see you?whom谁+N主、宾He is the man whom I saw yesterday?whose谁的+N定语Please pass me the book whose cover isgreen。

which哪个、物主、宾This is the house which we bought lastmonth。

关系代词as正主、宾、表As we all know，smoking is harmful toone’s health.when 什么时候There are occasions when(on which）aremust yield。

where 地点哪里Beijing is the place where(in which) Iwas born。

关系副词why表原因介词+whichIs this the reason why（for which） herefused our offer？❹关系词：连接先行词与从句的词称为关系词。

高一英语定语从句讲解及专项练习题(含答案)

一、基本概念（一）定语从句在复合句中作定语，修饰名词或代词的从句叫定语从句。

（二）先行词被定语从句所修饰的名词或代词。

一般情况下，定语从句紧跟先行词。

但也有因各种原因定语从句与先行词被分割的现象。

（三）关系代词和关系副词定语从句的引导词。

与先行词关系密切，因此紧跟先行词，并在定语从句中充当一个成分。

关系代词有：who, whom, which, that和whose, 另外，as也可充当关系代词。

关系代词在定语从句中充当主语、宾语、表语和定语。

关系副词有：when, where和why。

在定语从句中充当状语。

二、关系代词的用法（一）基本用法根据先行词的不同，和在从句中所充当的成分不同，选用不同的关系代词。

如下表：例如：（注意关系代词在定语从句中所充当的成分）①Do you know the professor who/that will give us a speech next week? （作主语）②I read a report about his new novel that/ which will soon be published. （作主语）③The plan that/which they argued about was settled at last. （作宾语）④This is the new secretary (who/whom/that)I would like to introduce to you. （作宾语）⑤The soldier whose legs were badly wounded was operated on without delay. （作定语）注意：关系代词在定语从句中充当宾语时可以省略，充当主语时则不能。

（见上例③④）（二）关系代词that代替which的一些情况which, that 在代替物时，一般可以通用。

但在有些情况下，只用that。

高中英语定语从句讲解及练习题含答案

高中英语定语从句讲解及练习题含答案定语从句是指修饰一个名词或代词的从句，用来限制或说明这个名词或代词的性质、状态、特点、数量等。

在英语中，定语从句使用的引导词包括关系代词who, whom, whose, which, that，以及关系副词where, when, why。

关系代词和关系副词的用法关系代词和关系副词的用法如下：关系代词：who, whom, whose, which, that1) who/whom/whose：用于人who：用于主语The man who is standing over there is my father.whom：用于宾语The woman whom I met yesterday is a doctor.whose：用于所有格The girl whose name is Lucy is my friend.2) which/that：用于物which：用于非限定性定语从句My house, which is near the park, is very quiet.that：用于限定性定语从句The book that you lent me is very interesting.注意：that 既可以用于人也可以用于物，但who/whom/whose 不能用于非限定性定语从句。

关系副词：where, when, whywhere：用于地点This is the school where I study.when：用于时间I still remember the day when we first met.why：用于原因This is the reason why I am late.定语从句的位置定语从句通常紧跟在被修饰的名词或代词后面，如果是用关系代词who, whom, whose, which, that 引导的定语从句，则可以省略该代词的主语或宾语成分，并将关系代词作为引导词。

【英语】必备英语定语从句技巧全解及练习题(含答案)含解析

【英语】必备英语定语从句技巧全解及练习题(含答案)含解析一、定语从句1．The building ________ Tony talked about is a famous restaurant named Nice Meeting you. A．who B．whichC．where D．whom【答案】B【解析】试题分析：考定语从句关系词的选择。

由题干可判断先行词为the building，为物，排除AD。

从句为不完整句子，先行词在从句中做宾语，故选B2．Linda will never forget the words her father told her.A．that B．who C．where D．what【答案】A【解析】【详解】句意：Linda将永远不会忘记她父亲告诉她的这些话。

that关系代词，引导定语从句，先行词可以为人或物；who关系代词，引导定语从句，先行词为人；where是关系副词，引导定语从句，在从句中作地点状语；what什么，常引导名词性从句，不能引导定语从句。

根据句子结构可知，这里是一个定语从句，修饰空前的the words，指物，且在从句中作宾语，故应选A。

3．This is the dictionary ________ Mum gave me for my birthday.A．which B．what C．whose D．whom【答案】A【解析】【详解】句意：这是那本母亲给我作为生日礼物的字典。

这里是定语从句，先行词是为物时用which；what不能引导定语从句；先行词指人时用who；当先行词为物主代词时用whose。

本题先行词为dictionary，字典是物，所以用关系词which。

故选A。

4．The girl ________ an English song in the next room is Tom’s sister.A．who is singing B．is singing C．sang D．was singing【答案】A【解析】【详解】句意：正在隔壁房间唱英文歌曲的女孩是汤姆的姐姐。

高中英语定语从句的用法讲解与专项练习题及答案

高中英语定语从句的用法讲解与专项练习题及答案定语从句的用法讲解与专项练习题及答案第1 讲关系词的选择技巧考点1. 相关概念基础过关1. 用合适的关系词完成句子。

1 The man / was here yesterday is a p ai nter.2 The man / / / I saw is call edSmi th.3 A child parents are dead is called an orphan.4 I’ｄlike a room window looks out over the se a.5 A letter / is written in pencil is hard to read.6 The letter / / I received from himyesterday is very important.7 That is the boy / / / youare looking for.8 Do you know the reason he was late for themeeting？9 This is the school I used to study.10 I still remember the day we met for the first time.考点2. 关系词的选择技巧A. 选用哪个关系词，关键是看关系词在定．语．从．句．中作什么成分含有定语从句的复合句可以分为两部分：主句和从句。

关系词是定语从句的一个成分。

选用关系词，要看关系词在定语从句中作什么成分，而不是看先行词是什么词性。

1 He worked in the factory which produces TV se ts.2 He worked in the factory where his father had worked.3 I like the school w hich is near to my home.4 I like the school w here my sister studies.在句①和句②中，先行词前都有in, 但关系词有用which 也有用where 的；在句③和句④中，先行词都是the school, 但关系词有用which 也有用where 的。

高中英语定语从句详解及习题精炼附答案

定语从句一、知识框架二、知识梳理一）定义(1) 定语从句：在主从复合句中用作定语的从句叫定语从句。

定语从句一般紧接在先行词后面。

(2) 先行词：被定语从句修饰的成份。

先行词可以为一个词，短语，或整个主句。

(3) 关系词：引导定语从句的词叫关系词，分为关系代词和关系副词。

关系词的作用：1) 引导定语从句，连接主句和从句，相当于一个连词；2) 必在从句中作某个句子成份（可以做主语，宾语，表语，定语，状语）关系代词（在从句中作主语，宾语，表语，宾补，定语）: that、which、who、whom、whose、as关系副词（在从句中只作状语）: when、why、where二）关系代词的用法在定语从句中关系代词起着连接主句与从句、指代先行词和在从句中作句子成分的三重作用。

关系代1. 关系代词who, whom和that的用法三者都可用于指代人，但在用法上存在差别。

who和whomwho可以代替人（即它的先行词必须是人），在从句中可以担任主语，往往也可以代替在从句中担任宾格的whom（常可省略）。

但它的前面不能有介词，如果带介词则必须用宾格whom,即“介词+whom”。

Johnny is a person who always has novel ideas.The girl who won the first prize is from Zhejiang.The person who/whom you just talked to is Mr Depp.= The person to whom you just talked is Mr Depp.We’ll go to the hospital to see the patients, most of whom are children.who和that在定语从句中who和that指代人时常可以通用，但在下列情况中只能用who,而不能用that。

(1)先行词是one, ones和anyone时，宜用who。

1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。

10.定语从句定从的本质是形容词，修饰其前的名词或代词。

与名从和状从最大的区别是其前有先行词。

一、定语从句在复合句中，修饰某一名词或代词从句叫定语从句，在句中起定语修饰的作用. 被定语从句修饰的词叫做先行词。

引导定语从句的词叫关系代词或关系副词。

如：Mary is a beautiful girl.Mary is a girl (who is beautiful). 定语从句先行词关系代词This is a book which was written by Tom who is my best friend.I remember the days____ I spent with you.I remember the days____ I played with you.I remember the place____ I visited last year.I remember the place____ I lived last year.I remember the reason____ I give to you.I remember the reason____ I was late.二．引导词注：这些引导词中有名词从句中的What，how，Wh—ever吗？三．引导词各自用法（Ⅰ）1．who修饰“人”作主语，口语中可作宾语。

T his is the man who often helps me.(who作主语)The man who you just talked is a teacher.2．whom修饰“人”作宾语。

可省略，但在介词后和非限制性定语从句中不可省略。

The doctor (who/whom) you are looking for is in the room.3．whose是who，which的所有格，作定语，修饰“人”“物”。

This is a book whose cover is blue.4.that修饰“人”“物”作主语、宾语、表语。

I want a man that/who understands English.He is not the man that he used to be.This is the picture that I bought yesterday.5.which(1)修饰“物”作主语、宾语。

The building which stands near the river is our school.(2)修饰整个句子，作主语、宾语I have to work on Sunday，which I don’t like.They tried to catch the bird，which was impossible.(3)修饰句子时，也可作定语，使句子更加明确。

He came back late，by which time all the guests had already left.I was told to go not by train but by bus，which advice I followed.6．as(1)在限制性定语从句中，若先行词被the same，such，as，so所修饰，从句的引导词用as，作主语、宾语。

I dislike such students as are careless.I’ll lend you as much money as you need.(2)作为关系代词，as可引导非限制性定语从句，修饰一短语或整个句子，也可插在句中。

As we know，the earth goes round the sun.The number of the visitors，as we had expected，was over two hundred. 关系副词when(时间)；where(地点)；why(原因)作状语(1)I still remember the day when I was born.(2)This is the house where I lived two years ago.(3)Can you tell me the reason why you did it?定语从句中的关系副词可由“介词＋which”来代替，以上(1)句中的when＝on which(2)句中的where＝in which(3)句中的why＝for which经典习题Ⅰ：1．I have seen the film，________leading actor is my favorite.A．its B．that C．whose D．which2．The girl ________everybody had thought could win a gold medal failed at last.A．who B．as C．what D．/3．Do you think the reason ________ he gave is believable?A．for which B．which C．why D．for that4．This is the job ________they laughed.A．which B．that C．at which D．at that5. Beihai Park is one of the most beautiful parks ________built about 300 years ago in Beijing.A．which was B．which wereC．that were D．where were6．On the table she found a piece of paper ________some puzzling secret codes. A．which was written B．that was writtenC．on which were written D．on that was written7．I don’t like the way ________he spoke to me.A．what B．by which C．by that D．/8．He makes good use of the time ________he can spare.A．that B．in which C．in that D．when9．It was a meeting ________importance I did not realize at the time.A．which B．at which C．its D．whose10．This is the factory ________they visited the other day.A．that B．where C．to which D．what11．He is not the same man ________ he used to be.A．/ B．which C．as D．what12．In an open boat，the four men，________a doctor，met with a storm on the sea.A．one of them was B．one of them wereC．one of whom was D．one of whom were创新预测Ⅰ：1．Only those ________ knew well could be let in.A．who B．whom C．he D．did he2．The boss，________department Mary worked，praised her greatly.A．whose B．in which C．in whose D．which3．His mother may come，in ________case I’ll ask her.A．that B．this C．which D．the4. Our teacher told us ________story ________we all never forget.A．so an interesting；that B．so interesting a；whichC．such an interesting；that D．such an interesting；as5．I still remember the days ________we spent together.A．when B．thatC．on which D．on that四．引导各自用法（Ⅱ）1．whom，which在定语从句中可作介词的宾语，这样的介词一般放在whom，which之前，也可还原。

that也可作介词宾语，但介词不能放在that前，只能放在原位置上；含有介词的固定词组，介词也只能放在原位置上。

This is the nurse to whom Tom spoke just now.＝This is the nurse whom Tom spoke to just now.The child whom you take care of is ill.2．定语从句中用that不用which情况(1)先行词是序数词或被序数词、形容词最高级以及the very，the only修饰。

This is the first film that I have seen at this cinema.(2)先行词为不定代词all，one，none，anything，everything，nothing，little，much，few等或被much，little，just，few，no，any，every等所修饰。

He has little time that he can spare.Is there anything that I can do for you？(3)当定语从句的先行词包括人或物时。

Look at the girl and her dog that are crossing the bridge.(4)前面已有疑问词who，which时，为避免重复。

Which is the book that you lost？Who is the lady that is playing the piano？(5)当先行词是疑问代词what时。

What did Tom hear that made him very sad？(6)当指人、物的关系代词作表语时。