Neville: You know, if you're interested in plants, you'd be better off with Goshawk's Guide to Herbology. Do you know there's a wizard i-in Nepal who's growing gravity-resistant trees?
Harry: Neville, no offense, but I really don't care about plants. Now, if there's a... Tibetan turnip that will allow me to breathe underwater for an hour, then great. But otherwise...
Neville: I don't know about a turnip. But you could always use gillyweed.
Harry's been wringing his hands for weeks to find a solution to his next challenge. Neville provides one in a few seconds.