1.they saw that boy go out
~~> That boy was seen go out.
2.betty has just sent Mary many post cards
~~> Mary just has been sent many post cards by Betty.
3.do they have to grow grass?
~~> Do grass have to be grown?
4.people call him pop singer
~~> He is called pop singer.
5.where do people speak English?
~~> Where is English spoken?
6.why did not they turn on the lights
~~> Why was not the lights turned on?
7.someone will tell him that news
~~> He will be told that news.
8.people saw him steal your car
~~> He was seen steal your car.
9.the teacher is watching them work
~~> They are being watched by the teacher work.
10.open your book
~~> Your book is opened.
11.take off your hat
~~> Your hat is taken off.
12.they made him work all day
~~> He was made work all day.
13.someone should look into the matter
~~> The matter should be looked into.
14.he likes people to call him "sir"
~~> People are liked by him to call him "sir".
15.he wants someone to take some potographs
~~> Someone are wanted by him to take some potographs.
16.one cannot eat an orange if nobody has peeled it
~~> An orange can not be eaten if nobody has peeled it.
17.dont let the others see you
~~> Aren't let you seen by the others.
18.did anybody ever teach you how to behave ?
~~> Are you taught how ta behave?
19.it surprised me to hear someone had robbed you
~~> I was surprised to hear someone had robbed you by it.
20.people ought to tell us how much they expect of us
~~> We ought to be told how much they expect of us.

1.  That boy was seen going out.
2. Mary just has been sent many postcards by Betty.
3.Do grass have to be grown?
4. He is called a pop singer.
5. Where is English spoken?
6. Why was not the lights turned on?
7. He will be told that news.
8. He was seen steal your car.
9. They are being watched by the teacher's work.
10. Your book is opened.
11. Your hat is taken off.
12. He was made work all day.
13. The matter should be looked into.
14. People are liked by him to call him "sir".
15. Someone is wanted by him to take some photographs.
16. An orange can not be eaten if nobody has peeled it.
17. Aren't let you seen by the others.
18. Are you taught how ta behave?
19. I was surprised to hear someone had robbed you by it.
20. We ought to be told how much they expect of us.