14．Scientists would like to place a huge mirror in space above the earth．It might be sixty miles wide．It would be used to catch the rays （光线） of the sun．It would direct the sun's rays upon the earth as a child might do to make sunlight dance on the wall with a hand mirror． Why do they want to do this？The sun's rays could be helpful in many ways．They could light up cities by night．The warm rays could stop frosts which might come at might and fruit crops．They could melt dangerous icebergs in the ocean．Perhaps they could change cloud movements and bring rain where it is needed． 54．The huge mirror wouldB． A．stand 60miles in height． B．be 60miles from side to side． C．cover 60miles of the earth． D．be 60miles above the earth． 55．The strong light from the mirror could possiblyC． A．hurt fruit crops． B．set fire to cities． C．bring longer daytime． D．shine through walls． 56．The underlined word"melt"probably meansD． A．反射 B．吸收 C．摧毁 D．融化 57．The huge mirror isC． A．something in a story． B．already made． C．just an idea． D．to be made soon．
