that和which在定语从句中只能作主语或宾语，而where在定语从句中只能作地点状语。that和which的相同之处：都可以作主语或宾语，都可以指代人或物。that和which的区别：that的三不用：1、非限制性定语从句只能用which引导，不能用that引导。2、紧跟在介词后面的关系代词不能是that。如：Give me a pen with which I will write an essay.3、关系代词后面有插入语时不能用that。如：Here is the gramma book which, as I have told you, will help you improve your English.比较：Here is the gramma book which/that will help you improve your English.that的六必用：1、先行词有形容词的最高级修饰，或有序数词修饰时，必用that。2、在不定代词，如：anything, nothing, the one, all, much, few, any, little等作先行词时，只用that，不用which。3、先行词既有人，又有物时，只用that，不用which。4、在there be 句型中，只用that，不用which。5、先行词有the only, the very修饰时，只用that。6、 关系代词在从句中作表语并带有类比含义时， 通常只用that， 不用which.例如： He is no longer the star that he was. 他不再是过去的那位明星了。
追问where的用法能否说详细点