"Io voglio un panino con formaggio ed un bicchiere d'acqua."
"I want a sandwich with cheese" is also as valid a response as "I want a cheese sandwich."
To me, "a cheese sandwich" and "a sandwich with cheese" are not the same. A "Cheese sandwich" is made up of cheese and bread, whereas a "sandwich with cheese" is some other kind of sandwich that you are ADDING cheese to. What is the meaning here?
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I think we Italian are not so strict with the "al/con/col formaggio" thing.
Of course "con" formaggio would suggest that there is other stuff as well, "al" e "col" would make think that cheese is the main ingredient, but I suppose that's very subtle and can be ignored.
I would like is a translation for io voglio offered by the "you peeked" drop downs, yet it was counted wrong. It is not, of course the subjunctive case, but is a nice way of translating instead of I want.