Hello ,who ______?is this are you is that is he

Hello ,who ______?is this are you is that is he

is that
哪位?（打电话常用）

who is that?

这句话要看语言环境了，如果是门口有门铃了，是who is it，如果是两个人见面了，那就是who are you ，如果是打电话的是who is that

is that speaking
打电话用语