听力原文：W: I'm exhausted. It took me about three hours just to buy a few things.M: What d

听力原文：W: I'm exhausted. It took me about three hours just to buy a few things.

M: What did you buy？

W: I bought a dozen cassettes.

M: How much did they cost you？

W: I bought them on sale. They were $ 20 a dozen.

M: Including tax？

W: No. I paid another $ 0.80 in tax.

M: So the tapes cost you $ 20.80.

W: Right. Only I had to take the subway to and from the store, so that cost me another $ 1.20.

M: So the cassettes really cost you $ 22 a dozen.

W: Right. Altogether I spent $ 22. What did you buy today？

M: A half-dozen cassettes.

W: You're kidding!

M: No. I had the same idea you had. I saw an ad in this morning's paper so I went down to buy them.

W: What did they cost you？

M: I bought them for $ 2 a piece, including tax.

W: So you spent $ 12 on six tapes.

M: Yes. And I bought them in the neighborhood so I spent only a few minutes shopping and I didn't spend any more money on transportation.

W: But my tapes still cost a total of $ 2 less than yours.

M: Sure, only you spent $ 22 on a dozen 60-minute tapes and I bought a half-dozen 90 minute tapes for $ 12.

W: Oh. It sounds like you really did get a bargain. But let's check out the quality of our tapes and find out if either of us really got a good deal.

M: We should have thought of that before we bought them.

W: True. But we didn't.

(20)

A．$ 20.

B．$ 22.

C．$ 20.80.

D．$ 21.20.