定语从句在考研英语中的重要性毋庸置疑。无论在完型还是阅读中，咱们同学们都会遇到各式各样的含有定语从句的长难句，大家一定要知道怎么识别以及理解它们，否则长难句对于大家理解起来就很困难。此外，大家还必须熟练掌握定语从句在写作中的运用，知道如何准确写出地道的、漂亮的定语从句，从而在写作这个模块能拿高分。写作如果能拿高分，考研英语分数就会漂亮很多。
　　定语是用来修饰、限定、说明名词或代词的品质与特征的。
　　主要有形容词，此外还有名词、数词、介词短语、动词不定式(短语)、分词，也有定语从句。汉语中常用'……的'表示。
　　定语和中心语之间是修饰和被修饰、和被的关系。
　　在复合句中起定语作用的句子叫定语从句。
　　例如：Harry Porter is a boy who has magic power.
　　译文：哈利波特是一个有魔法的男孩。
　　小结：定语从句=先行词 从属连词 句子
　　先行词：定语从句修饰的对象。我们要识别从句是否是定语从句，可以从从属连词切入。
　　句子一箩筐：
　　As we all know, Harry Potter is a novel that is famous around the world. It is also a famous movie which / (that) we all like watching. The main character(主角) Harry Potter is a boy who has great magic power and whom we love very much. The world where Harry Potter and his friends live is delightful, amusing and sophisticated. The place in which they stay is a grand castle whose roof is grey. The time when Harry Potter stays with his good friends is relaxing and unforgettable. It is the reason why so many people like this novel. Harry Potter turns out to be a great success, which is known to people around the world. Harry Potter is the book from which I learned much.
　　小结：定语从句的从属连词主要有两类：关系代词和关系副词。
　　关系代词主要有：that; who;which;as;whose N。
　　关系副词主要有：when;where;why。具体见以下表格：