定语从句请看下面的句子：I want to know the boy who is the tallest.（一）概念:定语从句：在复合句中修饰名词或代词的句子，叫定语从句。
先行词：被定语从句修饰的词叫先行词。
关系词：引导定语从句的词叫关系词。
（二）定语从句的分类Ⅰ、限定性定语从句：从句不可少，没有它，先行词的意思不明确，主句也不完整。
与先行词之间不用逗号。
e.g:This is the book that/which I want.Ⅱ、非限定性定语从句：是对先行词的补充说明，没有它不会影响先行词或主句意思的完整性。
从句一般用逗号同主句分开。
e.g:Mr. Green，who is watching TV，is my uncle.（三）(限定性)定语从句的结构Mary is a girl who has long hair.先行词关系词定语从句关系代词关系副词which, who, whom,whose, that where, when, why（四）定语从句的实质：二句合一（合并条件：人物先行在句一，又占句二一席地）Mary is a girl.合并为一个句子She has long hair.思路：留（保留先行词）-----舍（舍去与先行词互指的词）----替（用关系词代替舍去部分）Mary is a girl who/that has long hair.请把下列句子二句合一1. I saw the man.He closed the door2.The girl is happy. She won the race3.The man called the police . His wallet was stolen（五）定语从句关系词的确定:● a.先行词的分类● b.先行词在从句中充当的成分1.先行词做主语人：who/that物：which/that2.先行词做宾语人：who/whom/that物：which/that3.先行词做定语人：whose物：whose/of which 4.先行词做状语：w h e n,w h e r e,w h y●who, whom, whose, that用法区别.●who /that作定语从句的主语或宾语.The man who/that is speaking at the meeting is a worker. 做题思路：先分解——分析——再合并●Whom /that作定语从句的宾语The woman（whom/that) they wanted to visit is a teacher.分解The woman is a teacher.注意: 关系代词作动词宾语时可省略.●whose 作定语从句的定语.I know the girl whose mother is a teacher.分解I know the girl.The girl’s mother is a teacher.小结：关系词判断步骤●首先，要辨别出先行词。
如果先行词是指人,关系词可能就用who, that whom, whose。
如果先行词指物,关系词可能用which或that●然后，要确定关系词在从句中的成分。
请看下表先行词主语宾语定语人who, that who(m), that whose物which,that which, that whose,of which巩固练习：用适当代关系词填空1. I have a friend ________ likes listening to classical music.2. Yesterday Emily was wearing the new dress __________ I gave her.3. The man ______ leg broke in a match used to be a football player.（六）只能用that,不能用which的情况：(1)先行词为all, everything，anything，nothing, something, nothing ,few, little, much, the one 等不定代词时；(2)先行词被形容词最高级所修饰或被the only, the very, the last, any, few, little , no, all, one of 等修饰时：(3)先行词为数词或被序数词（含last)修饰时。
（4）先行词是并列词组既有人又有物时。
(5)在以who, which开头的句子中为了避免重复。
口诀：不定代词这一伙，全用that准没错先行词前有修饰，千万不能用which.请在以下例句中体会以上规则：1. Here is something that I will tell you.2.We haven’t got much that we can offer you.3. Is it the one that you want ?4.This is the most interesting story that I have ever heard.5. I can remember well the persons and some pictures that I see.6.Which is the bike that you lost?7.Who is the woman that was praised at the meeting?（七）只能使用w h i c h的情况●1.关系代词前有介词时；●2.先行词本身是t h a t时；●3.非限定定语从句●口诀:要有w h i c h别着急，●介词提前逗隔离。
●e.g:1.T h i s i s t h e c l a s s r o o m i n w h i c h w e s t u d i e d f o r t w o y e a r.●2.S h e h a s t w o d o l l s，w h i c h a r e f r o m h e r p a r e n t s单项选择：● 1. This is the bag _____ my mother bought yesterday.● A. that B. who C. whom D. this● 2. The girl _____ you saw in the street is Mary.● A. that B. whose C. which D. as● 3. Is this the factory _____ a lot of students visited yesterday?● A. the one B. which C. who D. whom●※4.Is this factory a lot of students visited ?A. the oneB. whichC. whoD. who● 5. The only language _____ is easy to learn is the mother tongue.● A. which B. that C. / D. it● 6. The girl handed everything _____ she had picked up in the street to the police.● A. which B. in which C. that D. all●※7. _____ cleans the blackboard should be praised.● A. That B. Who C. The one who D. The students who●注意：●①当关系词作定语从句的主语时，从句谓语动词的形式应与先行词的人称和数保持一致。
②若句中无先行词，先补出先行词再判断用法。
（4,7题）完成下列句子：1.这就是救了那个孩子命的医生.who saved the boy’ s lifeThis is the doctor2.正在跑步的那个人是我的叔叔.who is runningThe man is my uncle.3.我看见一位钱包丢失了的妇女。
I saw a womanwhose bag was stolen /whose bag was lost.4. 住在隔壁的那个小伙的是教师.The young man is a teacher.who lives next door注意：定语从句的时态不受主句影响。
【定语从句中考真题演练】1、There are lots of things ______ I need to prepare before the trip. (河北省卷)A. whoB. thatC. whomD. whose2、Jim dislikes people _______talk much but never do anything. （吉林省通化市）A.whomB.whenC.whoseD.who3、—I hear Sam has gone to Qiandiao for his holiday. （江苏省南京市）--Oh,how nice!Do you know when he_______?A.leftB.was leavingC.has leftD.had left4、We are trying to help those children ____lost their parents in Yushu , Qinghai Province. (浙江省衢州市)A. whichB. whenC. whoD. whose5、Do you know the girl _______is singing in the classroom? (湖南长沙)A.whoB.whichC.when6、—The volunteers are doing a great job in Yushu. （江苏省扬州市）--Yes.They are helping the people ______are suffering from the earthquake.A.whichB.whatC./D.who7、Have you found the answer to the question ______I asked you this morning? （四川省成都市）A.whenB.whatC.that8、Friends are those____ make you smile，always open their hearts to you and encourage you to succeed. （河南省）A whichB whatC whomD who9、I began to work in Shanghai in the year _____ HongKong was returned to China. （湖北省十堰市）A.thatB.whichC.whereD.when10、This is the school _______ I studied three years ago. （山东省菏泽市）A. whereB. whenC. thatD. which11、—What do you usually do in your leisure time? （黑龙江省哈尔滨市）—I enjoy reading in the library ____________ I lose myself in a world of good books.A. whichB. thatC. where12、—The village _________I visited last year has changed a lot. （福建省福州市）--Really?I hope to go there on day.A.thatB.whoC.when13、This is my beautiful school _______ is near the famous library. （广西省桂林市）A. whereB. whichC. whoD. when14、The old woman ______ is wearing a pair of glasses ______ Mrs. Black. （黑龙江省鸡西市）A. which, areB. who, areC. who, is15、Do you like music _______ makes you relaxed? （广西省定西市）A. itB. whatC. whoD. that。