1. It's everyone's duty to keep the enviroment clean.
->Everyone
2. It's her duty to make tea in the morning.
3. It's our duty to plant trees around the classroom.
4. It's their duty to help us.
6. The girl insisted on typing her letter.
7. They proposed buying some dictionaries.
8. Someone advised waiting for the last train.
9. She recommended raising some drivers.
10. The boy suggested hiring a car to drive to the beach.