i said "dlaczego dajesz mi klucze" and duolingo told me it was wrong. is it correct?
Yes, but you should use "dajesz" when you address one person and "dajecie" to address more than one person.
had the same problem. the question doesn't specify if we are addressing one person or two. it should accept both dajesz and dajecie .... i think
But it is accepted, moreover, it's one of two 'best answers' (it has to be, logically)...