=>
37. That experiment is being done by a student.
-> bị động HTTD is/am/are being V3/ed
38. We are given a free period this Sunday to prepare the festival by our teachers.
-> bị động HTĐ is/am/are V3/ed
39. Was this dictionary bought by you two weeks ago?
-> bị động QKĐ was/were V3/ed
40. Our teeth should be cleaned twice a day.
-> should be V3/ed
41. I am not impressed by Alan's knowledge about science and technology.
-> bị động HTĐ is/am/are V3/ed
42. All of us are driven to school by her father every day.
-> bị động HTĐ is/am/are V3/ed
43. Public transport will be used to go to school by students.
-> will be V3/ed
44. A great deal of electricity will be generated by solar power this summer.
-> bị động TLĐ will be V3/ed
45. Will the solar panels be installed on the roof of the house tomorrow?
-> Will S be V3/ed?
46. Plants won't be burnt to heat by local people this winter.
-> will/won't be V3/ed 
47. The air will be polluted by the smoke from factories.
-> bị động TLĐ will be V3/ed
48. A hydro power station will be built in this area.
-> bị động TLĐ will be V3/ed
49. I used to stay up late to watch football matches last year, but now I don't.
-> used to V : đã từng