Who - prepositions

[lindadanca]

Hello,

Could you please check whether the questions are correct or not.

1)I dont know whom you are talking to. (It is correct)

2)I dont know to whom you are talking. (It is correct)

3)I dont know who you are talking to. (It is correct)

4)I dont know to who you are talking. (Is it correct?)

I know that we can't use the prepositions behind 'who' with 'relative clause'.

For example, I know the girl to who you are talking. (It is not correct)

[J&K Tutoring]

#4 is incorrect

[lindadanca]

Thank you. But

I dont want to talk about who I am.

It is correct, isn't it?

[J&K Tutoring]

Yes, this is typical usage.