根据短文内容,用方框中所给单词的适当形式填空,每词限用一次。
Scientists would like to put a huge mirror in space above the earth. It might be sixty miles wide. It would be to catch the rays of the sun. it would direct the sun’s rays on the earth as a child might do to make sunlight on the wall with a hand mirror.
Why do they want to do this? The sun’s rays could be in many ways. They could light up by night. The warm rays could stop frosts(霜冻) which might come at night and hurt fruit and crops. They could melt(融化) icebergs in the ocean. Perhaps they could change cloud movements and bring rain where it is needed.