新概念英语第二册语法精粹七、定语从句一、定语从句1定语从句三步：第一找出先行词；第二看先行词在定语从句中的语法功能（做主语、宾语或状语）；第三选择合适的关联词。2定语从句在选择关连词that 与which时，常常容易出错，所以应记住什么时候只能用that，什么时候只能用which.（1）只能用 that 的情况归纳4种：即先得词被序数词最高级修饰过；先行词为all 、everything、nothing等不定代词；先行词同时是人和物并列时；最后先行词分别被the only 、the very the same、the last 修饰。请看下列四组例句，注意其先行词：The first thing that we should do is to work out a plan .I t almost seemed as if the good man were trying to teach us all that he knew at this lesson .Later my father and Mr.Crosset talke
