Change active into passive 4.People speak English and French in Canada 5.She Heard this song yesterday 6.Scientists have researched the UFO sinc

4. English and French are spoken by people in Canada 5. This song was heard by her 6. The UFO  have been reseached by scientists  7. Many friends had been invited for birthday party by Mary 8. A number of experiments on laboratory have been made by scientist  Вроде так