阅读下面短文，从短文后各题所给四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。

    Mr. Smith is a good teacher. He teaches English very well. He is1to his students， so they like him a lot. There are fifty students in 2 class. Mr. Smith always 3 English in class. He and his students are 4 friends， too.

    Now some of the students 5 on the playground. Bill and Mike 6. Tom and John are jumping. Mary and Lucy are 7 a kite. Are Lily and Maria flying a kite， 8? No， they are playing 9. What's Mr. Smith doing? Look! He is also playing 10them. How happy they are!