"Surely it is not a city?"
Translation:Num urbs est?
[ is it not? ] a facetious pretentious beg for positive affirmation of what is postulated to be of obvious unquestioned certainty:
Is it not a fact that; ... liquid water is wet?
Rome is an Italian city, is it not? [ Uh, duh, of course it is ]
[ Surely not ], begs for a negative confirmation:
Italy is surely not a Roman city, is it? [ Correct, although what is now Italy comprised territory of the Roman Empire ]
[ Say it isn't so! ] • begs for company to be in denial of a reality