A train stops at a station（车站）. A young man wants to come out, but it is raining. A boy is standing under a big umbrella. The young man says to the boy. "Can you go and get us two hambugers, one for you and one for me? Here are two dollars." "Great!" say the boy and he goes to buy hamburgers. After some time, the boy is back. He is eating a hamburger. "Where is my hamburger?" asks the young man. "Oh, there is only one hamburger left. So I'm eating mine. Here is your dollar. "
