提示：Sally每天下班时邮局都关门了，本周六她又要与几位朋友去郊游。她想请Peter为她买几张邮票，她把钱和写好的便条放在书桌上，可是Peter没注意。最后Peter明白了是怎么回事，答应给她买邮票。 (Sally=S;Petter =P) S :Did you find 51？ P: Yes. But what's it for? S:52 P : I didn't see any note. S : Well, I left a note saying I wanted you to get some stamps at the post office. P: Why can't you get them? S:53 when l get off work. P: You could  54 S:I know but I won'’t be in the town on $aturday. I'm going 54 P:Okay. I'll get them for you. What do you need? S ; I need a book of regular stamps and two of airmail. And thanks for doing it for me. P : lt's OK. You're welcome.