`text{39.The murdere hasn't been found by the police yet.}`

`text{40.He wasn't questioned very closely by the police.}`

`text{41.All the accounts can be done by the computer.}`

`text{42.A new school is going to be built.}`

`text{43.That building will be pulled down.}`

`text{44.The exercises won't be corrected by the teacher tomorrow.}`

`text{45.Dangerous chemicals have to be kept in the safe place.}`

`text{46.This room hasn't been used for ages.}`

`text{47.The problem can't be solved.}`

`text{48.Was an important speech made by the president last night?}`

`text{49.By whom is the passports being checked?}`

`text{50.Have you been paid by the customers?}`

39. The murderer hasn't been found by the police yet.
40. He wasn't questioned very closely by the police.
41. All the accounts can be done by the computer.
42. A new school is going to be built.
43. That building will be pulled down.

44. The exercise won't be corrected tomorrow.

45. Dangerous chemicals have to be kept in the safe place.

46. This room hasn't been used for ages.
47. That problem can't be solved.
48. Was an important speech made by the president last night ?
49. The passports are being checked by whom ?
50. Have you been paid by the customers ?