what.that.where.which.when.who.whom.为特殊疑问词用来引导特殊疑问句。that.which.who.whom.也是关系代词，在定语从句中为引导词，引导定语从句；where.when.也是关系副词，其在定语从句中作用同关系代词。
1.who指人，在从句中做主语
(1) The boys who are playing football are from Class One.
(2) Yesterday I helped an old man who lost his way.
2. whom指人，在定语从句中充当宾语，常可省略。
(1) Mr. Liu is the person (whom) you talked about on the bus.
(2) Mr. Ling is just the boy whom I want to see.
注意：关系代词whom在口语和非正式语体中常用who代替，可省略。
(3) The man who/whom you met just now is my friend.
3. which指物，在定语从句中做主语或者宾语，做宾语时可省略
(1) Football is a game which is liked by most boys.
(2) This is the pen (which) he bought yesterday.
4. that指人时，相当于who 或者whom；指物时，相当于which。在宾语从句中做主语或者宾语，做宾语时可省略。
(5) The number of the people that/who come to visit the city each year rises one million.
(6) Where is the man that/whom I saw this morning?
5. whose通常指人，也可指物，在定语从句中做定语
(1) He has a friend whose father is a doctor.
(2) I once lived in a house whose roof has fallen in.
whose指物时，常用以下结构来代替
(3) The classroom whose door is broken will soon be repaired.
(4) The classroom the door of which is broken will soon be repaired.
(5) Do you like the book whose cover is yellow?
(6) Do you like the book the color of which is yellow?
关系副词引导的定语从句
1. when指时间，在定语从句中做时间状语
(1) I still remember the day when I first came to the school.
(2) The time when we got together finally came.
2. where指地点，在定语从句中做地点状语
(1) Shanghai is the city where I was born.
(2) The house where I lived ten years ago has been pulled down.
3. why指原因，在定语从句中做原因状语
(1) Please tell me the reason why you missed the plane.
(2) I don't know the reason why he looks unhappy today.
注意：关系副词引导的从句可以由“介词+关系代词”引导的从句替换
(1) The reason why/ for which he refused the invitation is not clear,
(2) From the year when/in which he was going to school he began to know what he wanted when he grew up.
(3) Great changes have taken place in the city in which/where I was born.
五．限制性定语从句和非限制性定语从句
限制性定语从句举例：
(1) The teacher told me that Tom was the only person that I could depend on.
(2) China is a country which has a long history.
非限制性定语从句举例：
(1) His mother, who loves him very much, is strict with him.
(2) China, which was founded in 1949, is becoming more and more powerful.
要注意区分以下几个句子的不同
(1) His brother who is now a doctor always encourages him to go to college.
他那当医生的哥哥常鼓励他要考上大学。（他还有其他的哥哥）
(2) His brother, who is now a doctor, always encourages him to go to college.
他的哥哥是当医生的，常鼓励他要考上大学。（他只有一个哥哥）
难点分析
（一）限制性定语从句只能用that 的几种情况
1.who指人，在从句中做主语
(1) The boys who are playing football are from Class One.
(2) Yesterday I helped an old man who lost his way.
2. whom指人，在定语从句中充当宾语，常可省略。
(1) Mr. Liu is the person (whom) you talked about on the bus.
(2) Mr. Ling is just the boy whom I want to see.
注意：关系代词whom在口语和非正式语体中常用who代替，可省略。
(3) The man who/whom you met just now is my friend.
3. which指物，在定语从句中做主语或者宾语，做宾语时可省略
(1) Football is a game which is liked by most boys.
(2) This is the pen (which) he bought yesterday.
4. that指人时，相当于who 或者whom；指物时，相当于which。在宾语从句中做主语或者宾语，做宾语时可省略。
(5) The number of the people that/who come to visit the city each year rises one million.
(6) Where is the man that/whom I saw this morning?
5. whose通常指人，也可指物，在定语从句中做定语
(1) He has a friend whose father is a doctor.
(2) I once lived in a house whose roof has fallen in.
whose指物时，常用以下结构来代替
(3) The classroom whose door is broken will soon be repaired.
(4) The classroom the door of which is broken will soon be repaired.
(5) Do you like the book whose cover is yellow?
(6) Do you like the book the color of which is yellow?
关系副词引导的定语从句
1. when指时间，在定语从句中做时间状语
(1) I still remember the day when I first came to the school.
(2) The time when we got together finally came.
2. where指地点，在定语从句中做地点状语
(1) Shanghai is the city where I was born.
(2) The house where I lived ten years ago has been pulled down.
3. why指原因，在定语从句中做原因状语
(1) Please tell me the reason why you missed the plane.
(2) I don't know the reason why he looks unhappy today.
注意：关系副词引导的从句可以由“介词+关系代词”引导的从句替换
(1) The reason why/ for which he refused the invitation is not clear,
(2) From the year when/in which he was going to school he began to know what he wanted when he grew up.
(3) Great changes have taken place in the city in which/where I was born.
五．限制性定语从句和非限制性定语从句
限制性定语从句举例：
(1) The teacher told me that Tom was the only person that I could depend on.
(2) China is a country which has a long history.
非限制性定语从句举例：
(1) His mother, who loves him very much, is strict with him.
(2) China, which was founded in 1949, is becoming more and more powerful.
要注意区分以下几个句子的不同
(1) His brother who is now a doctor always encourages him to go to college.
他那当医生的哥哥常鼓励他要考上大学。（他还有其他的哥哥）
(2) His brother, who is now a doctor, always encourages him to go to college.
他的哥哥是当医生的，常鼓励他要考上大学。（他只有一个哥哥）
难点分析
（一）限制性定语从句只能用that 的几种情况
