Hermione said, eyes bursting with excitement. Ron rolled his eyes, "At this point I'd be surprised if you hadn't read about something. "Ron would you stop being such a dolt and just listen? Harry could use that to beat Malfoy and win the House Cup!" Harry perked up, but was as confused as ever. Could he really use this seemingly boring item to beat that smug prick?
Propositions are often metaphoric extensions of their literal meanings. Cerca is 'close' and cerca de is 'near to' and they are from the latin 'circa', meaning around. Same root as 'circle'.
Sobre is over, above, on, upon, atop (from the latin 'super', above).
They've both been extended to mean about. Neither translate "literally".