"Do you have this milk?"
Translation:Это молоко у тебя?
I've noticed a number of these don't accept Вы - is this to keep people starting out from getting confused between two forms, or is it just an oversight?
It is an oversight. Most sentences have them, unless stylistically it is unlikely you would adress this person informally ("Greetings, Igor Ivanovich") or formally ("Vanya, did you do your homework?")