Ex 4
A A strange object has been filmed in the sky (by a photographer).
B An unusual craft has been discovered in the Himalayas (by explorers).
C Thousands have been fooled by a Belgian UFO hoax.
D A new restaurant will be opened tomorrow by the mayor.
Ex 5
1 by 2 by 3 with 4 by with
Ex 6
1 were spotted 2 was captured 3 was observed 4 is being examined 5 has not been released 6 is believed 7 will be revealed