"How can you not know what shape it is?"
Translation:Jak możesz nie wiedzieć co to za kształt?
It doesn't have any English equivalent in the sentence, but is needed in such a construction. Compare with simpler sentences:
"Co to był za hałas?" - What was that noise?
"Co to był za fantastyczny mecz!" - What a fantastic game that was!
"Co to za kobieta?" - Who is that woman? (Yes, 'co' is used here and not 'kto')
Without 'za' the sentence either wouldn't make sense, or would ask to define the last word: What is "a woman"?
No, it's not that! That's what I tried to say with the last sentence, that it's not that. For example if you really had no idea what "a woman" is, in Polish you'd say: Co to jest "kobieta"? (Or: Kto to jest "kobieta"? if you at least understood that it's a human person)
It's hard for me to explain it differently than by putting these examples... it mostly implies either wondering about something (the examples with noise and woman, also let's say "Co to za zapach?" = "What's that smell?"), and sometimes it strengthens what you say as in the example with the 'fantastic game'. Also for example: Co to była za piękność... = What a beauty she was...
Thanks :) I mean, I didn't create it, but still ;) And I don't know if you can spend 'too much time' learning... ;)
The sentence you're referring to is "Przepraszam, nie znam tego kształtu." ("Sorry, I do not know this shape.") - grammatically it's constructed as 'to know X'. It's like saying "I am not familiar with this shape". Meanwhile here, it's grammatically "to know what this X is", so it's different.
So for example in these sentences 1 I know the sum of two plus two 2 I know what the sum of two plus two is 3 Do you know the metro 4 Do you know where the metro is 5 I know Pythagoras Theorem 6 I know how to prove Pythagoras Theorem
In 1,3 and 5 it is znac In 2,4 and 6 it is wieziec Is that right?