D There are two mice.Their names are Bill and Paul.They are good friends.One mouse lives in the countryside ; the other mouse lives in the city.On a sunny day they meet in the street. Paul: Hi , Bill ! Have a look at my house in the country.I ' m sure you can enjoy yourself. Bill: I ' d love to.But I hear that the food is not delicious , and your house is not good.Is it so? Paul: No , that ' s not true.Go and see! Then Bill goes to the countryside with Paul. Bill: Why do you live in a hole ( 洞 ) in the field ? You should come and live in the city.You should live in a nice house made of stone.You can have better food to eat.You must come and see me at my house in the city. Paul: Thanks ! Maybe you are right. Several days later Paul goes to Bill ' s house in the city.The house is big and beautiful.They are sitting in the sitting­room , having a big dinner comfortably.Suddenly , there is a great noise. Bill: Run ! Run ! The cat is coming! Paul: Oh , no ! It ' s terrible ! Both the house and the food are nice , but I do not like living in the city.I enjoy living in my hole in the field , for it is nice to be poor but happy than to be rich but afraid.