听力原文:W: Excuse me, sir. Can you tell me how much it costs to send an airmail letter to Paris? M: That's one dollar if it is not overweight. W: How about postcards? M: That will cost you 80 cents. W: Well, will you first weigh this letter for me? M: OK. The letter is 10 grams overweight, Madam. You'll have to pay 20 cents extra for the overweight. W: Here you are. And I want to buy a 30 cent stamp. M: Well. One 30 and 20 cents extra, that will be $1.50 altogether. W: Here's $2. M: OK. Here's your change. Have a nice day! W: Thank you! (8)