All the correct answers
How about this idea: if you hover over the correct answer of a question a window pops-up and shows all the acceptable answers. This way we don't have to guess if Duolingo accepts this or that answer as a correct one. Alot of coversation could be spared, and a lot of times saved. Instead of spending time asking if Duo accepts a certain answer or not we could just take a look ourselves. Would be sweet IMO.
It does not mention all of them all the time, sometimes it simply mentions the original translation answer. For example, in Spanish, if you drop the pronoun and simply put the conjugated verb, it will say the one with pronoun is also acceptable but may not include other sentences using synonyms or different re-arrangements of the sentence. Also, when you give the original translation answer coded in it often avoids giving you alternate answers.