"Wiemy co tam robiłeś!"

Translation: We know what you were doing there!

[pdforbes86]

listening to this slow, it still sounds like wiem and not wiemy

[BrianH71]

I think that's the nature of learning a new language. I constantly have that problem of not recognizing words as they are spoken, even when I know all the words. Keep practicing... :-) But, yes, the text-to-speech can also be poor or even a bit wrong at times.

[Mostlaszlo]

Prove it :P

[wutzelkrump]

Shouldn't 'We know what you were doing there!" be an acceptable answer?

[Jellei]

Yes. It's accepted, it should have worked.

[JanKLinde]

I don't believe that "...what you have been doing there" is a correct translation. Present perfect continuous denotes an action that is still going on in the present, and that doesn't match with the Polish past tense. Or can the imperfective aspect imply such a meaning?

[Jellei]

You're right. We changed the translation here.

[JuliaKanic1]

We know what you been doing there? Why not

[Jellei]

It needs "have", "what you have been doing". However, please see the comment above: https://forum.duolingo.com/comment/17414501?comment_id=52702841