定语从句定义1. 定语从句：在复合句中（一个句子的某一成分由句子充当），修饰某一名词或代词的从句；在句中起定语的作用。
两个首先必须明确的概念：先行词和关系词Kung Fu Panda is the best cartoon movie (先行词) that/which (关系词) I have watched this year.关系词分类关系代词：关系副词：关系代词的用法(1) that, which, who的用法关系代词例句that在从句中做主语或者宾语(后者可省略) 指___ 1)___________________________________.2)___________________________________. 指___ 1) ___________________________________.2) ___________________________________.which在从句中做主语或者宾语(后者可省略) 指___ 1)___________________________________.2)___________________________________.who在从句中可以做主语或宾语（后者可省略）指___ 1)___________________________________.2)___________________________________.Whom在从句中做宾语（可省略）指人(2) whose的用法关系代词whose为关系代词who的所有格形式，用作名词的限定语。
先行词既可为人，也可为物。
如：The girl whose English is very good wrote the novel.Whose=of which 指人的时候Whose=of whom 指物的时候例句1: To those who have been injured, happiness can simply mean a day without pain. 2: The person whom/who my teacher is talking to is my father.3: I like reading books which were written by O. Henry.4: I enjoyed the movie which you recommend to me.5: Their snowy mountaintops form a beautiful picture that surprises him a lot.6: There are many things that everyone can do to help stop pollution.7: Don’t get too close to the house whose roof is being repaired.8: Sam got an e-mail from the woman whose house we visited last week.由关系副词引导when在从句中作时间状语、where 在从句中作地点状、why在从句中作原因状语。
1) This was a time when the two countries were at war.2) Ancient China was a place where states were often at war with each other.3) This is the reason why he came late to school.◎如何判断关系代词和关系副词This is the city I was born.This is the city I visited last year.◎关系副词与“介词+ which”结构关系：why = for whichwhere = in/ at/ on whichwhen = during/ on/ in whiche.g.: O ctober 1, 1949 was the day when the People’s Republic of China was founded.Experience is a school from which you will never graduate.Each of us has a purpose for which we were created.非限制性定语从句非限制性定语从句起到补充说明作用，缺失也不会影响全句的理解，在非限制性定语从句的前面往往有逗号隔。
Ann received an album from Justin, which surprised her a lot.It is necessary to suggest the existence of an biological clock, which in some way measures and controls the aging process.◎限制性定语和非限制性定语从句的区别1: 非限制性定语从句中先行词跟定语从句用逗号隔开，限制性定语从句紧跟先行词，一般不加逗号。
2：He has a brother who is a singer.He has a brother, who is a singer.3：Ann bought an album, which costed her 100Yuan.Ann bought a lot of albums, which made her mother very furious.Fathers spend less time in housework and childcare, which is regarded by some scientists as a major cause for the stress of employed mothers.4：引导词的区别5: 相关考点I have a lot of friends, some of whom we have not seen each other for a log time.There is a hole, through which I can see everything in that room.◎由As 作为关系代词引导的定语从句1）用于限制性定语从句：It’s the same person as we wanted to find yesterday.There is such a warm house as we want to live inSuch...as the same ....as 像...一样的和...同样的2) 引导非限制性定语从句As we all know, Chinese government is terrible.Chinese government is terrible, which we all know.◎关系代词用that和which特殊情况1. Have you written down everything I have said?There seems to be nothing seems possible for him in the world.All can be done has be done.There is little I can do for you.2.It is the house in which we live.3. The first place they visited in London was the Big Ben.This is the best film I have seen.4: Ann passed the exam, which made their parents extremely happy.5. This is the very dictionary I want to buy.After the fire in his house, the old car is the only he owned.6. Who is the man is standing there?Which is the shirt fits me most?7:Can you remember the scientist and his theory we have learned?8.There is a room in the building is still free.9. She is no longer she used to be.◎关系代词只能用who/whom的情况1：This is Ann who is a big fan of Justin2: The man to whom my teacher is talking is my father◎关系代词只能用who/that的情况当关系代词指人时,关系代词既可用who,也可以用that.但在以下情况用who.1.当先行词是persons,people,those时.例如：Those who are for my plan ,please put up your hands.2.当先行词是he,one,all,any,they等时,例如：He who has not reached the Great Wall isn't a true man.3.在非限定性定语从句中用who.例如：I want him,who knows some English and French.在以下情况多用that.例如：5.当关系代词在从句中作表语时用that.例如：She is not the woman that she used to be.6.避免重复.例如：Who was it the man that you danced with last night?7.当先行词前面有形容词最高级、序数词或only等词修饰时.例如：I knew her father for the simplest,hardest working man that ever drew the breath of life. ◎练习现在的生活充满着各种压力源，其中的大部分是不可能避免的。
那些持反对意见的人认为我们必须放慢发展速度。
不少人认为如今被人们广泛使用的电脑未来总有一天将会彻底取代电视机。