Why not "Você terminou o seu trabalho?" ?
It's okay too.
I swear to God it sounds like I hear an "o" in the fast pronunciation, between "terminou" and "seu".
There could be an "o" there.
Would it be correct to say "Have you finished your job?"
Why not "You finished your work?"
It's also right
I totally agree with cazort. It's perfectly clear that in the fast pronunciation there is an "o" between terminou and seu. In the slow pronunciation there isn't, and Duolingo is right.
You finished your work was not correct. Looks like they adopted your proposal as the correct answer.