Scientists think that there has been life for_ _3 1 _ of years. However we haven’t found life on other planets _ 32_ . The earth is a planet and it _33_ _ around the sun. Seven other planets also go _ 34 _ the sun. The sun and its planets are __35 the solar system. The solar system is a small part of our galaxy. Scientists __ 36_ lots of spacecraft to look at other planets in the solar system, and some spacecraft have gone _ _37_ the solar system. However, no one _ _38 _ any life in space yet. But why has no one from other planets sent us a message ? Have they tried to send _ 39_ to us ? _ 40 _so many stars in the universe, are we alone, or is there life out there in space ? We don’t know. 小题1: A．thousands B．millions C．hundreds D．billion 小题2: A．already B．never C．yet D．just 小题3: A．go B．turn C．travel D．goes 小题4: A．to B．back C．around D．into 小题5: A．called B．call C．calling D．calls 小题6: A．send B．sent C．have sent D．will send 小题7: A．out B．beyond C．into D．up 小题8: A．discovered B．discovers C．has discovered D．have discovered 小题9: A．message B．informations C．information D．news 小题10: A．With B．Have C．Use D．Because