I am really confused by this. It gives the translation of "l'uva" as "the grape." It was my impression that l'uva actually referred to "grapes" in a general sense, perhaps in the way that one talks about "fish" in English, and one only ever used the plural if talking about different types of grapes (such as the different kinds of grapes used to make wines, etc). To refer to what we'd think of as "the grape" in English, wouldn't one have to say something like "il chicco d'uva"? Either way, this question doesn't clarify much for me.