Usages of nie wiem
Nie wiem, gdzie on jest.
I don't know where he is.
Nie wiem, czy ona wraca.
I don't know whether she is coming back.
Chyba tak, ale nie wiem.
Probably yes, but I don't know.
Nie wiem, o co chodzi.
I don't know what it is about.
Właściwie nie wiem, dlaczego.
Actually, I don't know why.
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