听力原文：M: Did you watch' Undersea Discovery' last night? W: No, I missed it. Did you? M: Yeah. It was pretty good--it was about barnacles. W: Hmm. M: You know how they stick themselves to stuff in the ocean－like rocks or boats? W: Uh-huh. M: Well, they do that when they're young, and then they stay in the same place forever. W: It figures. Have you ever tried removing one of those things? Last summer I tried to scrape some off a pier—I had to give up after a while. You'd think they wouldn't be able to stick like that underwater. M: Yeah. These biomedical researchers were talking about its possible uses. Orthopedists could use it for mending broken bones or it could be used in dentistry. W: I wish I'd seen that. (20)