你是谁英语怎么讲.?

看不见人的时候，比如说电话或是这个人在门外，就说Who's that? who's it?都可以。

如果这个人就在你面前，你可以说Who are you
反之，则用who is it 比如说有人敲门...
who is this 和 who is that 没什么大区别

如果是在接电话中..问别人是谁..!是不是用who is this呢??

Hey,girl,who are you?

who is this ?who is that ?是一样的 电话里的
Who are you?当面说的

面对面：who are you? (太直接，感觉起来生硬没有礼貌）
Do I know you?
What's your name.

电话里面：Who is this? Whos is that?