在复合句中，修饰某一名词或代词，用作定语的从句叫做定语从句。被定语从句所修饰的词叫做先行词。定语从句必须放在先行词之后。引导定语从句的关联词有关系代词who、whom、whose、which、that和关系副词when、where、why等。 如：finally, the thief handed everything that he had stolen to the police.最后，那个小偷向警察交出他偷的所有的东西。（引导词是关系代词that） his parentswouldn't let him marry anyonewhose family was poor.他父母不让他和家庭困难的人结婚。（引导词是关系代词whose） in the dark street, there wasn't a single person to whom she could turn for help.在那个黑暗的街道上，没有她可以求助的人。（引导词是关系代词whom）
