1.They must clean up the river.
The river has to be cleaned by them.
2.Tomorrow,we will clean the school.
Tomorrow,the school will be cleaned by us.
3.Are you clean the room everyday?
Is your room been cleaned by you everyday?
4.They are watering the flowers.
The flowers are watering by them.
5.Vegetables to make us more healthy.
We are made more healthy by eating vegetables.
6.The Jingde Town,a lot has changed in the past five years.
The Jingde Town has been changed a lot during last five years.
7.He wrote two of the E-mails yesterday.
Two E-mails were written by him yesterday.