听力原文：M: Hi, Vivian. What are you doing here? W: Hi, Steve. I'm having a bit of trouble finding some of the stuff I need. M: What're you looking for? W: Well, I'm just trying to find out something about the use of steel in building construction. Do you have any idea? M: Frankly, I don't know much about this. What about the library? There's a database on the computer, and most of the stuff you need is catalogued. You can find it somewhere. W: Yes, but that's the easy part! Then you have to find the book you want on the shelves, and you often find that it's out already. M: I know what you mean ! Then you have to line up to borrow it, if it's CTL. W: CTL? What's CTL? M: It means 'confined to library' : you know, it means you can't take it out. You have to read it in the library. W: 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. M: Hmm! In your shoes, I think I'd have a word with our tutor. W: I think I'll do that! Thanks! See you later. Bye! M: See yah! And good luck ! 23. What trouble is Vivian having now? 24.According to Vivian, what is the biggest difficulty in borrowing CTL books? 25.What does Vivian decide to do finally? (20)