一、定语从句的有关概念：在复合句中，修饰某一名词或代词的从句叫做定语从句。如：1)The man who/that lives next to us is a policeman. 2)You must do everything that I do. 在上面两句中的 man 和everything 是定语从句所修饰的词，叫先行词。定语从句放在先行词后面。引导定语从句的关系词有关系代词：that , which ,who (宾格whom ,所有格whose )和关系副词where, when .关系词（关系代词或关系副词）放在先行词和定语从句之间，起联系作用，同时又作定语从句的一个成分。也就是说关系词有两个作用： 1.引导定语从句。 2.代替先行词在其引导的定语从句中充当一定的句子成分。二、有关系代词引导的定语从句：关系代词 例句 That在从句中作主语或宾语(作宾语时that 可省略) 指物 1.A plane is a machine that can fly. (作主语) 2.The noodles （that） I cooked were delicious. (作宾语) 指人 1.Who is the man that is reading the book over there? (作主语) 2.The girl (that) we say yesterday was Jim’s sister. (作宾语) Which在从句中作主语或宾语(作宾语时可省略) 指物 1.The silk which is produced in Hangzhou sells well. (作主语) 2.The songs （which） Liu Dehua sang were very popular. (作宾语) Who, whom在从句中分别作主语和宾语（如果介词放在从句后面，则whom可以省略） 指人 1.The foreiger who visited our class yesterday is from Canada. (作主语) 2.The boy who break the window is called Roy. (作主语) 3.The person to whom you just talked is Mr Li. (作宾语) 4.Mrs White is the person to whom you should write. (作宾语) Whose 在从句中作定语 指人或物的所有格 I like the girl whose hair is long. (作定语) （从表中可以看出：用that 更有通用性）三、有关系副词引导的定语从句：(只作了解) 1. 先行词是表示地点的名词时（country, school, room…），而关系词代替先行词在定语从句中充当地点状语，一般用where引导定语从句。也可以用介词＋which的结构。值得注意的是which前介词的选择是根据先行词与介词的搭配关系而定.2. 先行词是表示时间的名词（year,month,day,night…），而关系词代替先行词在定语从句中充当时间状语，一般用when引导定语从句。也可以用介词＋which的结构。值得注意的是which前介词的选择是根据先行词与介词的搭配关系而定。