Mary likes music that is quiet and gentle 能把that 改用who吗?

不可以,因为先行词是MUSIC
加油!不明白再问!which 呢可以用which先行词是物时一般用that ， which ，但要注意下面情况；定语从句中只能用that ，不能用which的情况：1 先行词有序数词， 形容词最高级时或本身是序数词，基数词， 形容词最高级时只能用that2当被修饰的先行词为 all , any .much , many , everything ,anything , none ,the one 等不定代词时。3 当先行词被the ony ,the very , the same ,the last , little ,few 等修饰时4 当先行词里同时有人和物时。5 当主句是以who / which 引导的特殊疑问句时。只用which 不用that 的情况：1 当先行词为that , those 时。2 当关系代词前有介词时。如 What's thatwhic is under the desk ? This is the rom in which he lives .