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.