Viewing possible answers.
For the translation questions there are usually various possible answers. I think it would be nice to be able to see what all of the accepted answers are (after an attempt to answer has been made, of course). This would further expand the vocabulary of the user and improve his or her creative sentence construction abilities. This would be beneficial, not just for the language being learned, but for the native language as well!
I agree with this. Somewhere Duolingo seems to 'know' which word variations can still lead to a correct answer. I think it would be very valuable for us to be able to click a "show more" button and see at least some of the other answers. This would also help us acquire more synonyms in our vocabulary.
On my opinion it's not such a good idea. There are a lot of words with completely different meanings. Sometimes the meanings are depending of the usage of a special verb/word or context.
1) The Italian word "il campione" in English can be "the champion" but also "the sample, the specimen" (these words are not synonymous) So you have to look up the context and to check every sentence by your own to understand the meaning.
2) "alcuni" and "qualche" are both in English "some", they are synonyms. But I don't think that somebody - only by viewing them in the middle of many sentences - can notice the difference. The first is "some" in its plural form and the "second" in the singular form (alcune donne = qualche donna = some women).
Actually if you give the right answer they just give you an alternative solution. If you give a wrong answer you have enough to study to understand your errors and perhaps avoid them in the future. Too much information would only create confusion.
I would prefer the possibility to access directly from a sentence to some explanations (grammatical or about syntax or word meaning ....). Like a popup-window that you can display.