定语从句定义：在复合句中充当定语的从句叫定语从句。被定语从句修饰的词叫先行词，定语从句一般紧跟在它所修饰的先行词之后。在先行词和定语从句之间起连接作用的词叫关系代词。关系词有关系代词和关系副词两种。先行词 定语从句所修饰的词叫“先行词”。先行词通常为人、物或者是事情。I am reading the article that is about your experience in the UK.关系词 从意义上说：先行词是定语从句的组成部分从结构上说：先行词不能在从句中出现 所以用关系词引导定语从句，并取代先行词在从句中做某种成分。 I am reading the article that is about your experience in the UK.关系词的功能1. 关系词作主语The trees are on the school campus. They have lost their leaves.The trees which are on the school campus have lost their leaves.2. 关系词作宾语We saw the student just now. He is the best runner in our school.The student whom we saw just now is the best runner in our school.3. 关系词作表语Jack used to be a lazy boy. He is no longer a lazy boy Jack is no longer the lazy boy that he used to be.4. 关系词作定语（通常为所有格）She has a brother. I cant remember his name.She has a brother whose name I cant remember.5. 关系词作状语（时间状语、地点状语、原因状语）The school is in Shenzhen. He studies in the schoolThe school where he studies is in Shenzhen.提示：关系词在定语从句中有两大作用1. 连接作用连接先行词和定语从句。 I gave her all the money that I had. （that 连接先特词 money和定语从句I had）2. 成分作用在定语从句中作主语、宾语、定语或状语。 I like picrures which are painted in the traditional Chinese style. （which在定语从句中作主语）关系代词引导的定语从句who, whom, which, that, as, whose等跟在先行词的后面，指代先行词，引出定语从句。 在从句中充当主语、宾语、表语、定语的作用。1. who和whom当先行词是表示人的词语时，用who或whom。who 可作主语和宾语。作宾语时可用whom，that替换，也可省略。whom只作宾语，通常省略。The man who spoke at the meeting this morning is a famous lawyer.The girl who you saw just now is Jane.The girl whom / who / that you saw just now is Jane.2. which当先行词是表示事物的词语时用which，可在从句中作主语和宾语，作宾语时可省略。This is the book which was written in English by our English teacher. The pictures which he drew in the 1980s are on show.注意(whom & which)： whom & which做介词宾语时，介词常可提前，即介词+whom/which+从句，此时whom & which不能由who或that代替，不能省略。This is the man from whom your son always begs money.The chair on which she is sitting is made of wood.但当介词置于从句末尾时，whom可以由who或that代替，which可由that代替，都能省略。This is the man (whom / that / who) your son always begs money from.有一些动词短语中的介词是固定搭配，不可拆开，一般还是放在动词之后，不提前。 He is the student who the teachers are looking for.The number of the children who she takes care of is 30.动词短语是否可以拆分，关键看拆分后与拆分前的意思是否相同。如果意思不变，可以拆分，否则不行。 3. that的用法无论先行词是表示人或事物的词语时都可以用that， that可作定语从句中的主语（取代who或which），宾语（取代who或whom或which） that的特殊用法必须使用that的情况。1）当先行词是人+事物时。They talked about the teachers and schools that they had visited.The police had great trouble in diverting the men and the cars that had blocked the way.2）当先行词跟在系动词be后作表语，或关系词本身作定语从句的表语时，关系代词必须用that，但也可以省略My father is no longer the man (that) he was. He thought his daughter would be the dancer (that) she always wanted to be. My father is no longer the man (that) he was. My hometown is not the small town that it used to be twenty years ago.3）当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. He was the first person that passed the exam. This is the best film that I have ever seen.This is the first choice that I have made.She is the most careful girl that I have ever known.4） 当先行词前面有the only, the very, the same, the last等词修饰时。The only person that seems to know the truth is Doctor Brown.This is the last letter that I received from him. This is the very grammar book (that) I want to buy. Beauty is the only thing (that) Emily can be proud of. 5) 当先行词本身为不定代词如anything, something, nothing, everything, all, much, few, little, none, the one或被不定代词修饰时。All that I want is peace and stability.There is little that I can do.There is nothing that I can tell you.I have tried everything that I can think of.I do not mean this one. I mean the one that was bought yesterday.注意：anybody, nobody, everybody等不在此列。 不能使用that的情况。1) 当定语从句前有介词时，关系代词不能用that。2）当先行词为one, ones, anyone, those, 指人时，用who。Those who learn not only from books but also through practice will succeed.3）当先行词是he时，用who。(多谚语) He who plays with fire gets burnt.He who laughs at last laughs best.4）当先行词本身是that时，用which或who避免重复。Whats that which flashed in the sky just now?5) that不能用于非限制性定于从句。4. whose的用法 whose作定语从句中的定语，表示所修饰的“某（些）人的”或“某物的” 。 The boy whose name is Tom is the top student in my class.Look at the house whose roof is red.注意： 当whose指代物时，whose+ n =the +n+of which=of which the +nLook at the house whose roof is red.Look at the house, the roof of which is red.Look at the house, of which the roof is red.I saw some trees whose leaves were black because of the polluted air. 5. as的用法在限制性定语从句中，as可跟在由such, so, the same修饰的先行词之后，可做主语和宾语。 Such men as heard him were deeply moved. Ive never heard such stories as he tells. He lifted so heavy a stone as no one else can lift.比较：the same as 和the same that the same as强调相同，the same that注重同一She wore the same dress as her younger sister wore.（as指的是与先行词相似的同类事物）She wore the same dress that she wore at Marys wedding. （that指的是与先行词同一事