"Why are you crying?"
Translation:Varför gråter du?
Not that it really answers the "why" but the pattern is simply [question-word] [verb] [subject] [optional other stuff].
I think English is the language that should explain its logic :-). In English the participle of the verb to cry seems to function as an adjective. Compare with Why are you sorry? which translates into Varför är du ledsen? in a straight forward way.