用括号内所给动词的适当形式填空。

1. More trees and flowers should _________ (plant) to make our hometown beautiful.

2. We must do everything we can _________ (keep) waste water from running into rivers.

3. When I was young, my grandfather told me that the sun _________ (rise) in the east.

4. Would you mind _________ (not smoke) in public?

5. John _________ (chat) with his son while his wife was cooking in the kitchen.