1.定义：定语从句时在复合句中修饰名词或代词，充当定语的句子.其位置在其所修饰词之后.它的作用相当于形容词或介词短语.定语从句所修饰的词叫先行词.引导定语从句的词叫关系词，包括关系代词和关系副词.2.关系代词：that指人或物，在句中作主语、宾语或表语 who指人，在句子作主语或宾语 whom指人，在句中作宾语 whose指人或物，在句中作定语 which指物，在句中作主语或宾语3.关系副词：when时间状语，where地点状语，why原因状语(1)who指人，在从句中作主语.在口语和非正式语体中常用who作宾语，可以省略.Eg:In the Yushu earthquake,the number of people who were killed reached as many as about 2700. Here are some people who/whom you want to see.
