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