who指代的部分在从句中做主语, She is the person who told me the story. whom指代的部分在从句中做宾语 She is the person whom I played with yesterday.或者 She is the person with whom I played yesterday.
第一句里面who指代person,在从句里面是主语,也就是说,后面的句子完整的应该是 the person tole me the story 第二句里面whom还是指代person, 但在从句里面做with 的宾语,跟with一起构成状语,后面的句子完整的状态是 I played with the person yesterday