定语从句的引导词
定语从句的引导词有两类：
一）关系代词
当先行词表示人时，引导词用who/that(在从句中作主语或宾语）/whom（在从句中只作宾语）/whose（在从句中作定语，后接名词）;
当先行词表示事物时，引导词用which/that(在从句中作主语或宾语）/whose(在从句中作定语，后接名词）。
1.Do you know the person who/that is standing under the tree?
2.I prefer the book which/that you showed me just now.
3.Look at the building whose walls(名词） are yellow.
注意：1）what和how不能引导定语从句；
2）引导词在定语从句中作宾语时可省略，但引导词所代替的那个宾语应该去掉；
如：Do you know the man (who/that/whom)I talked to just now?
在talked to后面不能再来一个宾语him,因为已经用引导词who/that/whom代替him作talked to的宾语了。
3)如果把介词提到引导词前面时，先行词表示人，引导词只用whom,先行词表示事物，引导词只用which,即人+介词+whom和事物+介词+which。如上面一句也可以表达成Do you know the man to whom I talked just now?
4)先行词是 a way/the way/ways时,引导词可用that/in which或省略引导词。
5)下列情况只能用 that (不用 which) 来指代物
(1)先行词为 all, much, little, something, anything, everything, nothing 等不定代词时。如:
I will do everything that I can do to help you. 我将做我能做的一切事情来帮助你。
(2)先行词是最高级或者被形容词的最高级修饰时。 如:
This is the most important task that should be finished soon. 这是必须马上完成的最重要的任务。
(3)先行词为数词或被序数词修饰时。 如:
You are the first men that like the kind of book. 你们是第一批喜欢这种书的人。
(4)先行词中既有人又有物时。 如:
We were deeply impressed by the teachers and schools that we had visited. 我们访问过的老师和学校给我们留下了很深的印象。
(5)当先行词前有 the one, the only, the last, the very, any, few, little, no, all 等词修饰时,引导词只能用
that。如:
He is the only person that knows the truth. 他是唯一知道真相的人。
(6)当主句中已经含有疑问词 who 或者 which 时,只用 that。 如:
Which is the bike that you lost? 哪一辆是你丢的自行车?
6)非限制性定语从句不能用that引导。
二）关系副词（在定语从句中作状语）（高中阶段学习）
当先行词表示地点时，引导词用where;
当先行词表示时间时，引导词用when;
当先行词表示原因时，引导词用why。
选择定语从句的引导词既要根据先行词表示什么，也要根据引导词在定语从句中的作用来确定。试对比：
1.I still remember the school which/that（作从句谓语的宾语） I visited (及物动词）last year.
2.I still remember the school where（在从句中作状语） I taught（不及物动词） for ten years.
