At school, we have thirty minutes' rest (放松) between classes. Most (大多数) of us are playing for 30 minutes. Some students are on the playground. They are having a basketball game. Oh! A boy is running with a ball. And another one is trying to stop him. They are so cool. And there are some girls watching the game. Some students are in the classroom. They are talking. Some of them are reading or doing homework. Look! A girl is looking at the birds (鸟) in a tree in front of the classroom. She must be thinking of something interesting because she is smiling (微笑). What are the teachers doing? Do you know? Some of them are working in the office, and some are talking with students. Everyone (每人) is busy with his or her things, busy but happy.