I wrote "Da dove vieni tu?" and was marked wrong! Most irritating!
Da dove venivi? is supposd to be marked as correct. Is this not the "imperfect" tense, where did you you used to come from? If so I'm calling b.s. as there are no lessons on the imperfect up to now, unless I'm sleeping that is.
"Di dove sei?" is accepted.
Could it be "Da dove tu vieni?"?
"Da dove tu vieni" is not a question. If you want to use the subject (but you normally don't use it in Italian) in a question, then you need to put it after the verb, like in English.
To me that sounds like "from where do you you come from". Can a wonderful Italian confirm this?