定语从句定义:在复合句中，修饰主句中某个名词或代词或修饰整个主句的句子叫作定语从句。先行词：被定语从句修饰得的名词或代词注意定语从句必须位于先行词之后定语从句一般由关系代词和关系副词引导 关系代词的用法Who 指人，主格，在从句中可作主语和宾语Whom指人，宾格，在从句中只作宾语Eg(1): The boys who are planting trees on the hill are middle school students.（主语）Eg(2): The woman who whom I met yesterday is an artist. （宾语）Eg(3): The girl who I talked to just now is my friend. Which只指物，在从句中从句中作主语和宾语This is the house which I lived in last year.Or This is the house in which I lived last year. eg: The book which you gave me yesterday belongs to my deskmate. That：即可指人，又可指物，在从句中从句中可作主语和宾语. 指人可与who互换;指物可与which互换The girl that is speaking at the meeting is our monitor. (who)This is the book that he is looking for.（which）I like the music that I can dance to.He prefers the food that tastes delicious.Exercises:Exercises:用定语从句把每组两个句子用定语从句把每组两个句子合成一个句子合成一个句子1.This is the factory. I visited it last week.2. The boy is my brother. You spoke to the boy just now.3. I still remember the year. We spent the year working together.4 The book is well worth reading. I give you the book.5. The photograph might be mine. You have found it under my desk. 6. We dislike the people .the people are dishonest.7. I would like to talk to those people . They look friendly.8. You can look up the word in the dictionary .you dont know the words. 用适当的关系代词填空1. Ill never forget the days _ I spend with Tom.2. The story _ you told just now is unbelievable.3. This is the student _ we all take pride in.4. The lady _ my English teacher is talking to is our head master.5 .She wants to buy big house_ she cant afford.定语从句（1）限制性定语从句，用来限制先行词的意义，在讲话时不需要停顿，书写时无逗号。引导词：关系代词：that, which, who, whom, whose, as 关系副词: when, where, whyEg: Do you know the girl whose mother works in this school.I know the student whose handwriting is good.This is the bike that I lost last year（同一个）This is the bike as I lost last year（相似）(2)非限制性定语从句与先行词关系松散，对主句的某一内容其补充说明作用。 朗读时有停顿，书写时有逗号。引导词有：引导词有：关系代词关系代词which, who, whom, whose(谁的）谁的）,as关系副词关系副词where, when, 注意：注意：that , why不能引导非限制性定语不能引导非限制性定语从句从句Eg: His new house, which lies at the foot of the hill, was built last year.We get to the school on time ,where we study every dayAs it is known to all， practice makes perfectExercises:1. Ill never forget the days_ I spend with Tom.2. Ill never forget the days_ I lived in Beijing.3. This is the point _ you should pay attention to.4. The notebook _ Im writing on is lost.5. The book _ _ I heard is written by Lu Xun.6. The reason _ Pets told us is unbelievable.7. The reason _ Mary is so sad is that she failed to pass the exam.8. This is the student_ _ we are proud.9. I live in the room,_ windows face the south.10. Wang, _ was my monitor, has gone abroad.注意：以下5种情况只用that1先行词是先行词是all, everything, nothing, anything, little, much, the one等不定代词等不定代词2 当先行词当先行词all, any, every, no, some, little, much被修饰时。被修饰时。3先行词被序数词或形容词最高级修饰时。先行词被序数词或形容词最高级修饰时。4先行词被先行词被the only, the very(正是，恰是正是，恰是), the same, the last修饰时修饰时5当先行词有两个或两个以上时，即有人又有物当先行词有两个或两个以上时，即有人又有物时时不用不用that的情况有的情况有 ：6、不位于介词之后、不位于介词之后7、不引导非限制性定语从句、不引导非限制性定语从句