Post Office A

the certified mail: 挂 号 信, correo certificado, البريد المسجل

the postage:  邮费, 邮资, coste de envío, تكلفة إرسال بالبريد  
to overnight a letter or to send a letter by overnight mail: you send it today; it arrives early tomorrow morning, 帮我次晨达这(个)包裹 , por correo urgente,  مستغرق ليلة واحدة 
to cost: 价 格 为, costar, يكلّف           
to get there:  to arrive there, 到達在, llegar, يصل (إلى مكان مدينة أو بلدة)

1.   Ask me how much stamps for Vietnam are.

      Answer:  How much are stamps for Vietnam?
3.   Tell me you want to send your package to L.A.  
      Answer:  I want to send this package to L.A.
5.     Ask me what the cheapest way to send it is.
      Answer:  What is the cheapest way to send it?
7.   Tell me you would like to send your letter by certified mail*.
      Answer:  I would like to send this letter by certified mail.
9.     Tell me you want to send your package to Vietnam.
      Answer:  I want to send this package to Vietnam.
11.  Tell me it needs to get there before May fifth.
      Answer:  It needs to get there before May 5th.
13.  Ask me how much the postage is to send this letter to Burma.
      Answer:  How much is the postage to send this letter to Burma?  

Post Office: Student B

2.     Tell me you want to send your letter to Hong Kong.
        Answer:  I want to send this letter to Hong Kong.
4.     Ask me how long it will take to get there.
        Answer:  How long will it take to get there?
6.     Tell me you would like to overnight* your letter to NYC.
      Answer:  I would like to overnight this letter to New York City.
8.   Ask me how much it will cost.
        Answer:  How much will it cost?
10.   Ask me what the fastest way is to send this letter to NYC.
      Answer:  What is the fastest way to send this letter to New York City?
12.   Ask me how much insurance costs for your package.
      Answer:  How much does insurance cost for this package?