... UNIT 10 LIFE ON OTHER PLANETS A- MULTIPLE CHOICE : 1- Have you ever seen ________ UFO in your life ... ________ stars. ( fall, fell, fallen, falling) 9- The shooting star ________ so fast that I can't see it clearly. ( appears, shows, sights, sights) 10- UFOs means _______ flying objects. A- unknown ... They cannot show the shapes of the UFOs ______________. (clear) 9. Stories about UFOs are always ___________________. (mystery) 10. Once a man is on a space trip, he seems to be in a________________...