Ex1 complete the sentences whit the words or pharses in the box : galaxy,planet, flying saucer, solar system, astronaut, outer space, space buggy, weightless, aliens, traces                                                                           1.A______is sometimes referred to as an unidentified flying object(UFO) 2 An_______is a person who is trained for travelling in a space craft 3 Resear chết made the amazing finding of______water on Mars 4 A______is a vehicle used for driving on the moon 5 Our___is made up of the sun and all the objects that travel around it 6 Earth is the only known to he habitable to _____life 7 Do you believe______exist on other planets? 8 Space craft are vehicles used for travel in____ 9our____the Milhy way,consists of 100-400 billion stars 10 Astronauts on the orbiting space stiom are ____because they do not experience a force of gravity