B1-C1 Passive voice review
Turn to passive voice: She made the chocolate cake for the birthday.
The chocolate cake was made by her for the birthday.
Turn to passive voice: They have seen strange lights in the night sky.
Strange lights have been seen in the night sky.
Turn to passive voice: They will give the winner a gold medal.
The winner will be given a gold medal. / A gold medal will be given to the winner.