"Have you watched the news yet?"
Translation:Bạn đã xem thời sự chưa?
Not exactly. khong is yes or no, chua is "not yet", so the question is asuming that either you did already or your are going to do.
Also, "chua" can be a reply, meaning not yet.
- ban da di cho chua (did you go to the market yet)
- chua (not yet)
(for me it's a little confusing that the word means "not yet" instead of "yet")