2. whom指人，在定语从句中作宾语。例如：

　　Do you know the young man (whom) we met at the gate？

　　Mr Lee (whom) you want to see has come.

　　3. whose 指人，在定语从句中作定语。例如：

　　The girl whose mother is ill is staying at home today.

　　I know the boy whose father is a professor.

　　4. which指物，在定语从中作主语或宾语。例如：

　　A dictionary is a book which gives the meaning of words.

　　Here is the book (which) the teacher mentioned yesterday.

　　5. that多指物，有时也指人，在定语从句中作主语或宾语。例如：

　　I’ve read the newspaper that(which) carries the important news.

　　Who is the person that is reading the newspaper over there？

　　6. when 指时间，在定语从句中作状语。例如：

　　I’ll never forget the time when we worked on the farm.

　　He arrived in Beijing on the day when I left.

　　7. where 指地点，在定语从句中作状语。例如：

　　This is the house where we lived last year.

　　The factory where his father works is in the east of the city.

　　四. 关系代词 whom， which 在定语从句中作介词宾语时，可以和介词一起放于先行词与定语从句之间，有时为了关系紧凑也可以将 whom 与 which 与先行词紧挨着书写，而将介词置于定语从句的后面，如：

　　That was the room in which we had lived for ten years. = That was the room

　　which we had lived in for ten years.

　　五. 具体使用时还要注意下列问题：

　　1. 只能使用that，不用which 的情况：

　　(1) 先行词是all， few， little， nothing， everything， anything 等不定代词时。例如：

　　All that he said is true.

　　(2) 先行词被only， no， any， all，等词修饰时。例如：

　　He is the only foreigner that has been to that place.

　　(3) 先行词是序数词或被序数词修饰的词。例如：

　　He was the second (person) that told me the secret.

　　(4) 先行词是形容词最高级或被形容词最高级修饰的词。

　　This is the best book (that) I have read this year.

　　(5) 先行词既包括人又包括物时。例如：

　　He talked about the people and the things he remembered.

　　2. 只能用which，不用that 的情况：

　　(1) 在非限制性定语从中。例如：

　　The meeting was put off， which was exactly what we wanted.

　　(2) 定语从句由介词+关系代词引导，先行词是物时。例如：

　　The thing about which he is talking is of great importance.

　　考查的主要形式是单项填空、完型填空、短文填空和完成句子。阅读理解和书面表达肯定也要用到定语从句。