定语从句是中学英语教学的重点，也是学生学习的难点，同时又是高考考查的热点。纵观近年各地高考试题，对定语从句的考查不单纯考查其语法结构，而是把它融入到一定的语境中，考查考生的实际综合运用能力。因此掌握这一语法现象十分重要，现就此归纳如下：
一、如何选择引导定语从句的连词
选择怎样的关系代词或关系副词来引导引导定语从句，不是由先行词来决定，解题时要进行必要的语法分析，注意题干的内容和句子的结构，尤其要看其在定语从句中充当何种成分以及它是限制性的还是非限制性的定语从句，从而确定使用关系代词还是使用关系副词。
(1) In an hour, we can travel to places ______ would have taken our ancestors days to reach. A. where B. when C. which D. what (06’上海卷)
(2) Anyway , that evening , ______ I will tell you about later , I ended up staying at Rachel’s place . (04’浙江卷) A. when B. where C. what D. which
(3) Is this the reason ____ at the meeting for his carelessness in his work? (02’上海)
A. he explained B. what he explained C. how he explained D. why he explained
二、有关定语从句高考考点归纳
考点一：考查that与which的区别