My uncle has two dogs .One is big and the other is small. He likes them very much.
One day, his friend Mr. Smith came to visit him. When Mr. Smith saw two holes in the door ,a large hole and a small hole, he was surprised and said ,“My dear friend ,why are there two holes in your door ? ”My uncle answered, “ Let my dogs come in and come out, of course. Mr. Smith asked, “But why are there two holes? One is enough! ” “But how can the big dog go through the small hole ? ”my uncle said.