Exercise 1: Change the following sentences into passive form.
29. His story isn't believed.
30. More hospitals must be built.
31. I am advised to eat more vegetables and fruits.
32. The theory of gravity was studied by Newton when he was over 20.
33. Everything will be checked carefully before we go.
34. The window of the lab has been changed.
35. Big cakes are being made for the party.
36. The work had been finished before we came.
37. The test must be finished before 10.
38. The children was being brought home at 4:30 p.m.
39. Chinese and French are taught here. English isn't taught.
40. 200 people will be invited to the wedding party.
41. Something must be done to help the poor in this city.
