Mr. Brown lives on Green Street now. He wants to send a postcard(寄明信片) to his pen friend in Toronto, but he doesn't know where the post office is. “ where is the post office？” he asks his new neighbor Joe. “I want to send a postcard to Toronto.” “The post office is quite far from here，” answers Joe. “If you only want to post some letters(信件) or postcards, you needn't go to the post office. You can put them into a mailbox（信箱）down the street.”