Do you want a friend whom/who/that you could tell everything to?
Do you want a friend to whom you could tell everything ?可以讲解一下么，为什么to提前只能whom。帮我相关相关拓展一下。因为指人时，直接位于介词后作宾语只能用whom。指物时，直接位于介词后作宾语只能用which.