which指代物，that指代人和物，当先行词后有动词时只能用which不能用that
，当先行词是人时用that当先行词是物时可用that，which，那么that，which在先行词都是物时有什么区别呢？可用四句口决来概括“that，which可互换，下列情况请照办。不定代词这一伙，全用that准没错，先行词前有修饰，千万不要用which 。想用which别着急，介词提前逗隔离。”
