Помогите с английским, пожалуйста. Пассивный залог, виды инфинитива

Re-write the sentences in two ways. Put the underlined parts in the passive.
1. They say that a fire has completely destroyed the Royal Hotel.
It ...is said that the Royal Hotel has been completely destroyed by a fire... The Royal Hotel ...is said to have been completely destroyed by a fire...
16. They say that the fire is still burning. It
The fire
17. They think that the fire started in the kitchen.
It
The fire
18. They believe that ambulances have taken fifteen people to hospital. It
Fifteen people
19. They report that seven people are in a serious condition.
It
Seven people
20. They believe that a cigarette started the fire.
It
The fire
21. They expect that the police will investigate the cause of the blaze.
It
The cause of the blaze