dialogue c
（a: guest b: receptionist）
a： good afternoon, my room number is 321. any mail for me？
b： yes. you have two letters and one telegram, also a message was left by a lady before one hour.
a： let me see who called…？i have to make a phone call.will you get me the party？here is the number.
b： ok. wait for moment…here is your party.
a： thank you.i'll mail a letter to u.s.a. by airmail. how much do i have to pay for you？
b： a letter generally mall to america- europe- africa by airmail. first 20 grams is 20 yuan.each additional 20grams is 15 yuan.
a： oh, i see. thank you very much.