I39;m in the park. I can see some children. They ......

I39;m in the park. I can see some children. They ...... playing volleyball. There39;s my friend Greg! He ...... reading a book. The girl .......eating a sandwich. The boy and the dog ........playing with a ball. They can39;t see me because I ...... sitting in a tree. What ...... you doing? ........ you listening to me?