"Do you know us?"
Translation:Kennst du uns?
My warning was - You used the you form "Kennst" instead of the they form "Kennen".
I thought Sie was formal 'you'. God, 'you' has to be the hardest part of basic german by far.. it's so damn confusing!
Lowercase "sie" is "they," but it can be capitalized at the beginning of a sentence. The formal you form of "Sie" is always capitalized.
i already used this construction in other answers (questions) and it was correct
I read somewhere that in german the questions must always begin either with a verb or with question word (what, how, when, where, which...)
Proper German structure for questions is question word (Welche, wie, wo, etc.), verb, subject. In this case there is no question word, so it would be Kennst du uns?
You could but you have to conjugate the verb kennen properly: "Kennt ihr uns?" (not sure if duo will accept it though...)
Why would "hast" be in there? The verb "have" isn't in the English sentence, if it were, the sentence wouldn't make any sense. So why would it make sense in the German?