54. It is thought that he has died a natural death.

      He is thought to have died a natural death.

55. It is believed that 13 is an unlucky number.

     13 is believed to be an unlucky number.

56. It is said that John is....

      John is said to be the brightest student in class.

57. It was reported that the President ...

      The President was reported to have suffered a heart attack.

58. They were known to have told him of the meeting. 

59. She was declared to win the competition. (o làm cách 1 nữa nha vì ctrúc của nó đơn giản lắm)