Unit 5, Prelim. Ex., 7. raises an interesting question.
"Patriam populi territi invadere non debetis"
Is it "you ought not invade -- you should stay away from their country" or "you don't have to invade -- there is no obligation to invade"? In other words, does "non" here negate the action or the obligation to act? I _think_ it ought to be the latter but, then, I'm not a Roman.
And if it's the one, ...