A young man is sitting by the road, He is eating something. A policeman is coming over. At once the man stands up quickly and runs down the road. The policeman runs after him. The man runs very fast, but the policeman runs faster." After a few minutes, the policeman catches him. “Where are you going?" says the policeman. “You must be a criminal(罪犯) if you run like that when you see a policeman,” “No, no,” says the man. “I'm not a criminal. I'm just too fat, you see, and the doctor tells me I must always run fast after eating.” “I see,” says the policeman.“ You are running to help to lose weight.”