求高手细细讲解下定语从句which和that的使用区别

which只能指代物，that既可指代人也可指代物，所以先行词既有人，又有物时，只能用that

介词后不能用that，而which可以

which可以引导非限制性定语从句，that不可以

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。

先行词有the only, the very修饰时，只用that

先行词为序数词、数词、形容词最高级时，只用that

1先行词是everything、nothing、anything等不定代词时，用that而不用which。
2但先行词是something时that为最佳which也不算错。
3先行词是all、any、many、much、little、few等不定量的代词充当是that，不用which。例All who should be here are present at the meeting.
4先行词被the very、the most修饰时用that，不用which。
5先行词被形容词或副词最高级修饰时用that，不用which。
6先行词为sb或sth时用that而不用which
7先行词在主句或从句中充当表语时用that而不用which。
注意that前不加介词
当先行词是that时为避免重复用which