My grandma's favourite animal is a cat. She likes cats very much. She has two cats in her house. The white cat's name is Mimi, and the black one is Dingy.  Mimi is nine years old. She's an old cat now. Her hair is always dirty. She can't run fast and when she sees a mouse, she lets it go. Dingy is six years old. He is a young cat. He is always clean and tidy. He can run very fast. Dingy is much stronger than Mimi. So he can catch more mice. Every time when he got a mouse, he shared（分享） it with Mimi, because they are good friends.