At the post office 在邮局
基本词汇：
send 寄，送
parcel 包裹
Shanghai上海
by air mail用空邮
by ordinary mail/by surface mail 用平邮
主要句型：
I want to send this parcel to Shanghai. 我想把这个包裹寄往上海。
Do want to mail it by air or by ordinary mail?您是要寄空邮还是平邮？
情景会话：
A: Good morning, sir. May I help you?
先生，早上好。有事吗？
B: Yes, I want to send this parcel to Shanghai.
我想把这个包裹寄往上海。
A: Do want to mail it by air or by ordinary mail?
您是要寄空邮还是平邮？
B: Ordinary mail is OK.
平邮就行了。