When I was in school, I was told in class that adverbs generally end in -ly. "Really?" I asked. "Are you sure? Ugly, lovely, friendly, silly, elderly, wily, curly?" Having anticipated this, I had memorized this list, waiting for the right moment, to see if I could pull it off. Sure enough, the teacher looked briefly confused, then said "Oh, right, it's adjectives that tend to end in -ly." And the class dutifully wrote it down.