A student raises her hand and asks me what 'show up' means.
"To show up," I explain "means to arrive or come or appear."
"A~h . . ." After chewing on it for a moment, she gives me a peevish look and grumbles, "Didn't we do this before?"
By "this", she means the worksheet I have given her. It's a page from a textbook I've been putting together and trying out in various classes to find any mistakes or poorly worded sentences.
"Possibly," I tell her. "Then again, if you're so smart, why are you having to ask me what 'show up' means for the second time?"
"Ah, solly . . ."