Mrs. Black is a fifty-year-old woman. She lives in a beautiful house in a small town. She has two cats. One is very big and the other is quite small. She likes them very much. One day, Mrs. White, a friend of hers, comes to see her. When she sees two holes(洞) in the door, a large hole and a small hole. She is very surprised and says: “ My dear friend, why are there two holes in your door?”

       “Let the cats come in and go out, of course.” Mrs. Black answers.

       “But why are there two holes? Isn’t one enough?” asks her friend.

       “How can the big cat go through the small hole?” Mrs. Black says.

31. Mrs. Black lives in a tall building.

32. Mrs. Black has two cats. One is old and the other is young.

33. Mrs. White thinks one big hole in the door is enough.

34. Mrs. White loves her cats very much.

35. Mrs. Black thinks big cat goes through the big hole

and the small cat goes through the small hole.