In English, I would say, "A glass of juice," or, "A cup of juice," or, "A kind of juice," or, "A type of juice."
In Romanian it can mean all of those things.
Bear in mind though that many sentences are forced to stress the usage of the language that you are learning. It's something common all over Duolingo.
On the other hand, if you see a mistake or an alternate translation, please report it.
Duolingo gave me a "Select the missing word" question. It said "un..." and the options were "suc" or "cafea". I selected "cafea" and it said this is wrong. Is it a different gender or something?
Yes, just our luck, "cafea" is feminine and would be "o cafea" and "ceai" is masculine and would be "un ceai", but "suc" is neuter which uses the masculine definite ending in singular "un suc" and feminine definite ending in plural.
Yes because it says to type "what you HEAR", aka the Romanian not the English translation.
Could anyone please explain in simply way the cases of nouns N,J,D,A....thanks in advance.
Do Romanians not also say "un cafea"? Seems a strange question.
No, that would be "o cafea" since it is feminine in Romanian, scroll up for more information. Genders do not match from language to language.