"You do not eat lunch?"
Translation:Bạn không ăn trưa?
Exactly otherwise it's a statement, you do not eat lunch and do you eat lunch are very different
Dualingo is not exactly in this stituation. Vietnamese people don't say "Bạn không ăn trưa?", we usually say "Bạn không ăn trưa à?" (in English "You don't eat lunch, do you?") when we are almost sure he doesn't eat lunch. Do you eat lunch? Then the sentence is similiar to "Bạn có ăn trưa không?" In Vietnameae
That would make two "không", two negatives in a short sentence. Instead you should say "Bạn không ăn trưa sao?"
Excuse me?! No only is "bữa" not needed but it also is written the same as "You don't eat lunch."?
Bạn không ăn bữa trưa is fine, in my opinion you should put the question particle à/ư at the end to smoothe it...