阅读对话，回答下列问题。
Mary: Hello! Lucy! Let's go to the post office. I want to send a letter.
Lucy: OK. Let's go. I want to send some postcards.
Mary: Where do you send your postcards?
Lucy: I'll send them to America. And where do you send it?
Mary: I'll send it to Canada.
Lucy: How much are the stamps?
Mary: I think ten yuan.
Lucy: That's too expensive. Let's send an email.
Mary: I think so. Let's go!
1. Where do Mary and Lucy want to go?
2. What do they want to do?
3. Where will Mary send the letter?
4. Where will Lucy send the postcards?
5. How much are the stamps?
