11. The gardener has planted some trees. 
Some trees have been planted by the gardener.
12. Doctor Brown will give you some advice.
I will be given some advice by Doctor Brown.
13. A famous designer will redecorate the hotel.
The hotel will be decorated bt a famous designer.
14. Someone has broken the crystal vase.
The crystal vase has been broken.
15. His parents have brought him up to be polite.
He has been brought up to be polite by his parents.
16. Fleming discovered penicillin.
Penicillin was discovered by Fleming.
17. They will advertise the product on television.
The product will be advertised on TV.
18. Someone is remaking that film.
That film is being remade.
19. Picasso painted that picture.
That picture was painted by Picasso.
20. Did the idea interest you?
Were you interested by the idea?
11. You must leave the bathroom tidy.
The bathroom must be left tidy.
12. You should water this plant daily.
This plant should be watered daily.
13. Our neighbor ought to paint the garage.
The garage ought to be painted by our neighbor.
14. I have to return these books to the library.
These books have to be returned to the library.
15. People know him well.
He is known well.
16. You must dry-clean this shirt.
This shirt must be dry-cleaned.
17. They started a dancing class last week.
A dancing class was started last week.
18. Mr. Smith saw the accident.
The accident was seen by Mr. Smith
19. The teacher returned our written work to us.
Our written work was returned to us by the teacher.
20. People spend a lot of money on advertising every day.
A lot of money was spent on advertising every day.