which that用法区别：that和which在定语从句中都是做关系代词,指代先行词是事物的名词或代词（that还可以指代人，which不可以）通常情况下二者可以互换。

1.先行词是all,anything,everything,nothing等,关系代词应用that。 That's all that he told me.2.先行词前有the only,the same,the very 或no,little,much,any,every,all 等修饰时,关系代词应用that。She is the only person that I know in this company.1.非限制性定语从句中关系代词一般要用which。She won the competition,which made the whole family very happy。