阅读理解，根据短文的意思，选择最合适的答案。

    It's seven forty in the morning. The children are coming into the classroom. A girl is opening the windows. Some are laughing and talking. Some are listening to them. Some are reading books. Some are doing their homework.

    Miss Gao is standing behind the teacher's desk. She is writing on the blackboard. Sue and Han Mei are wearing their new dresses today. Ann is cleaning her desk. Mike is helping her. They all look happy.

What are Bill and Lin Tao doing? Oh, dear! They are still playing basketball!