定语从句的十大考点修饰名词或者代词的从句叫做定语从句。
被修饰的名词或者代词叫先行词；定语从句的引导词叫关系词（关系代词&关系副词）；定语从句分为限定性定语从句和非限定性定语从句（前有逗号隔开）引导定语从句的关系代词有：that which who whom whose as关系副词有：when where why定语从句的十大考点1. that 与which 在指代物时的用法区别that 和which都可以引导先行词为物的定语从句，但是用法有区别：(1) 只能用that的情况a.先行词为everything，all，little，much等不定代词时；b.先行词被all，every，no，any，some，little，much，one修饰时；c.先行词被the only，the very，the same，the last修饰时；d.先行词被序数词或形容词最高级修饰时；e.先行词是be的表语或there be 的主语时；f.先行词有人又有物时；g.当主句是以who或which开头的特殊疑问句时。
(2)只能用which的两种情况a.非限定性定语从句中b.关系代词前面有介词时Galileo built a telescope through which he could study the skies.2．which与as的区别as 和which 都可以引导非限制性定语从句，三种情况下只能用as，不能用whicha. as置于句首引导定语从句时（As we know,…）b. as 含有“正如”之意（…as we expected）c. 先行词前有such, the same 修饰时（…such an easy question as the little boy can answer.）As is often the case等。
3. who、whom、that 的区别a.先行词为指人的不定代词时，如those或people 时，常用关系代词who,不用thatb.介词之后用关系代词whom引导定语从句c.当先行词是一个限定性的表示人的特定名词时，不用that.如：The aunt who came to see us last week is my farther’s younger sister.4. whose 用法“whose”表示谁（可以为人也可以为物）的（东西）例：A child whose parents are dead is called an orphan.（“whose parents”表示那个孩子的双亲）He lives in a room whose window faces south.（“whose”表示那个房子的窗户）whose 表所属关系指物时，可与of which 转换，词序一般是：名词+ of whichLook at the building , the roof of which ( = whose roof )is white .5. 介词+关系代词引导定语从句的用法a. 介词之后的关系代词只能用which（先行词为物）或者是whom（先行词为人）b. 介词的选择方法有三个原则：一“先”二“动”三“意义”I lost my pen, with which I took notes. (先行词为pen,使用钢笔用with)This is the house in which he lives. (定语从句中谓语动词live为不及物动词)The gas is oxygen without which we can’t live. (根据句意决定)6. 先行词为way时先行词为way，在定语从句中作状语时，用that，in which引导定语从句，也可以省略关系词。
e.g. I don’t like the way(that/in which) he speaks to his parents.7. 关系副词when、where、when引导定语从句的具体用法①先行词表示时间、地点、原因时，在定语从句中作状语，选择相应的关系副词when、where、why引导定语从句。
若其在定语从句中作主语或宾语，则选择关系代词引导定语从句。
区别三组例句：a. This is the place where he lives.a. This is the place that/which he visited last year.b. I still remember the time when my brother was a little boy.b.I still remember the time that/which we spent together.c. This is the reason why he was late.c.This is the reason that/which he gave us.②某些非地点时间名词用定语从句修饰，关系词在从句中作状语，由where引导定语从句（stage, case, point, situation,position）；同样用法的还有occasion,由when引导定语从句。
e.g. I can think of many cases where students know a lot of words but don’t write a good essay.There are many occasions when people don’t know what they want.8. 定语从句中的谓语动词关系代词在定语从句中作主语时，定语从句中的谓语动词应该与先行词保持一致。
e.g. Anyone who wants to have a holiday puts up your hand.Those who want to have a holiday put up your hand.This is one of the students who have passed the exam.This is the only one of the students who has passed the exam.9. 区分定语从句和其他句型①区别于简单句和并列句There are 70students in our class , most of whom are boys. (定语从句)There are 70students in our class , and most of them are boys. （并列句）There are 70students in our class . Most of them are boys. （简单句）②区别于强调句型It is in the factory that he works. (强调句型)It is the factory where he works. （定语从句）③区别于同位语从句The news that she had passed the exam excited us.（同位语从句：对名词解释说明）The news that he told us excited us. （定语从句：对名词修饰限定）④区别于状语从句Do you know the time when the class is over? (定语从句，有先行词)Let’s play games when the class is over.（时间状语从句，无先行词）Put the book where it belongs. (地点状语从句，无先行词)10. 定语从句中关系词的省略定语从句中，作宾语的关系代词可以省略，介词之后的关系代词不可省略。
This is the house which he lives in. (√)This is the house he lives in. (√)This is the house in which he lives. (√)This is the house in he lives. (×)练习题：I.用相应的关系代词或关系副词填空。
1. He_______makes himself a sheep shall be eaten by the wolf.2. I know the reason_________he was angery.3. You can take anything______you like.4. Our hometown is no longer the one______ it used to be .5. He is a man ______we should learn from.6. There is a teapot shaped like a Chinese duck, out of ______mouth tea is supposed to come.7. In the dark street, there wasn’t a single person to_______ she could turn for help.8. He came the day _________I was out.9. I live in the room_________he used to live.10. Have you asked him the reason _________may explain his success?11.An ecosystem consists of the living and nonliving things in an area ______interact with one another.12.The book has helped me greatly in my daily communication, especially at work ____ a good impression is a must.13.________is often the case with children, Amy was better by the time the doctor arrived.14. A company _____profits from home markets are declining may seek opportunities abroad.15.He wrote a letter ________ he explained what had happened in the accident.II. 用定语从句翻译下面的句子。