Mr. Hundert, a pedantic and demanding classics professor, would be unlikely to make the error of saying that Caesar's army was "comprised of" two legions. He would have said that Caesar's army comprised two legions, or that two legions composed Caesar's army, or that Caesar's army was composed of two legions. A trivial error, perhaps, but out of character nonetheless.
When the students are caught on the brink of skinny-dipping, one of the nuns is wearing a wimple (traditional headgear and veil) together with a habit that has an above-the-knee skirt. You would never see a nun wearing such a combination.