Passive
1.They believe that their son will buy some food
->It
->Their son
->Some food
2.They think that the students are doing their test carefully
->The students
->The students' test
3.They rumour that this naughty boy will be punished
->The students' test
4.People think that Mr. Lee has written this novel
->Mr. Lee
->This novel
Passive
1.They believe that their son will buy some food
->It is believed that their son will buy some food.
->Their son is believed to buy some food.
->Some food is believed to be bought by their son.
2.They think that the students are doing their test carefully
->The students are thought to be doing their test carefully.
->The students' test are thought to being done carefully
3.They rumour that this naughty boy will be punished
-> this naughty boy is rumoured to be punished
4.People think that Mr. Lee has written this novel
->Mr. Lee is thought to have written this novel
->This novel is thought to have been written by mr lee
