It is sunny today .My mother, my father and I are going to the park. We like the park very much. It is very big and beautiful .There are many trees and flowers in it. Many people like to go there. Look! An old man is sitting on the chair. He is reading a book carefully. Two boys are jumping on the ground. Their mothers are talking with each other. Two birds are flying in the sky. The ducks are swimming in the river. They are very happy. What is the cat doing? Oh, it is running after a mouse. It’s a poor mouse.
(1)What +be (am,is ,are)+主语+v.-ing+其他?
(2)主语+be(am,is ,are)+ v.-ing+其他。