用所给的词的适当形式填空。

1. Xiao Gang spends much time _________ ( play) computer games.

2. The little boy has only eight _________ (tooth) now.

3. Will you ________ (take) part in the long jump ?

4. I think I must do my best _________ (improve) my English.

5. You must do sports to keep _________ (health).