"Who is he?"
Translation:Quis est is?
It should also be accepted now, but unfortunately it takes some time for the changes we make in the Incubator to be active for users (sometimes as long as two weeks).
Still, please report (with the button in the lesson, not in the discussion) if it's not accepted, it's still possible something got missed!
"-ne" is an interrogative enclitic only used in yes/no questions (in less grammatical terms, it's something stuck on the end of a word to mark that this is a yes/no question and not a statement). When there's a question word, skip "-ne".