adjustable录音原文中提到有六个搁板，其中两个是固定的(fixed)，另外四个则是可调节的(adjustable)。

B: Hello?
C: Oh, hello I’m ringing about the advertisement in yesterday’s newspaper... the one for the bookcases. Can you tell me if they’re still available?
B: We’ve sold one, but we still have two available.
C: Right. Er, can you tell me a bit about them?
B: Sure, er, what do you want to know?
C: Well, I’m looking for something to fit in my study. So, well, I’m not too worried about the height, but the width’s quite important. Can you tell me how wide each of them is?
B: They’re both exactly the same size, let me see. I’ve got the details written down somewhere. Yes, so they’re both 75 cm wide and 180 cm high.
C: OK, fine, that should fit in. OK. And I don’t want anything that looks too severe… not made of metal, for example. I was really looking for something made of wood.
B: That’s all right, they are, both of them.
C: So, are they both the same price as well?
B: No, the first bookcase is quite a bit cheaper.It’s just ￡16. We paid ￡60 for it just five years ago, so it’s very good value. It’s in perfectly good condition, they’re both in very good condition in fact, but the first one isn’t the same quality as the other one. It’s a good sturdy bookcase, it used to be in my son’s room, but it could do with a fresh coat of paint...
C: Oh, it’s painted?
B: Yes, it’s cream at present, but as I say you could easily change that if you wanted to fit in with your colour scheme.
C: Yes. I’d probably paint it white if I got it. Let’s see, what else... how many shelves has it got?
B: Six, two of them are fixed, and the other four are adjustable so you can shift them up and down according to the sizes of your books.