"Tomorrow you will all receive your grades."
Translation:I morgen modtager I alle jeres karakterer.
There is a conflict between the translations. In the english one all refers to pupils but in the danish alle refers to grades. Tell me if I'm wrong.
Yes and no, the danish sentence is ambivalent. It could be about all the pupils or all the grades.
It should be karakterer. Duolingo also wants vil instead of skal, if you're going to use an auxiliary verb; but it seems to me that skal should be accepted too. I'm not a native speaker though.
Since du is singular, that would translate to "Tomorrow you will receive all your grades." But that is not the same, in English, as the desired "Tomorrow you will all receive your grades." In the first English sentence "all" modifies "grades," but in the second "all" modifies "you."
This is a guess, but maybe the problem is just that it's not as close a match to the word order in English, and its emphasis on "tomorrow."
I don't know whether or not the two Danish versions sound equally idiomatic.