听力原文：Hu: Hi, John! John: G'day, Hu! How's it going? Hu: All right! But I'm having a bit of trouble finding some of the stuff I need. John: Really! What're you looking for? Hu: Well, I'm just trying to find out a bit about the use of steel in building construction. Have you any ideas? John: Yeah! Well, speaking offhand, that should be straightforward enough. What about the library? There's a database on computer, and most of the stuff you need is catalogued—you should be able to find it somewhere or other. Hu: Yes—but that's the easy part! You then have to find the book you want on the shelves, and you often find that it' s out already. John: I know what you mean! Then you have to line up to borrow it, if it's CTL. Hu: CTL? What's CTL? John: It means 'confined to library': you know—it means you can't take it out. You have to read it in the library. Hu: It seems easy, doesn't it but you have to reserve it, and then you may want to photocopy bits of it, or make notes — and there never seems to be enough time! John: Hmm! In your shoes, I think I'd have a word with your tutor. Hu: I think I'll do that! Thanks! See you later, Bye! John: See yah! And good luck! Question : What is the stuff that Hu is looking for? (23)