2017届高考英语总复习闯关密训卷 Unit4《Sharing》选修7_高考复习指南

2017届高考英语总复习闯关密训卷 Unit4《Sharing》选修7

　　C. does good to other people and is respected and loved by them

　　D. has made a lot of money for himself before he dies

　　NASA’s Mars detector (探测器), Opportunity, succeeded in finding signs that water once existed on the planet. Opportunity landed on Mars in January. Scientists now believe that the planet could once have supported life.

　　This discovery was chosen by Science, one of the world’s leading magazines, as the most important scientific achievement of 2004 last Friday.

　　“This little, wheeled, one-armed box went around another planet and has done something no human has ever managed,” according to Science. “It has discovered another place in the universe where life could once have existed.”

　　“Although we still can’t say that life could have existed in this environment, it is now certain that there was water on Mars,” said Steve Squyres, one of the scientists working on the Mars mission. The evidence comes from pictures and chemical readings taken by Opportunity. It includes marks on rocks like those caused by flowing water on Earth and salty chemicals like those found in dried-out sea-beds. Scientists said the new evidence proved beyond doubt that water has existed on Mars. But it is still unknown whether the water on Mars was like an ocean or just ice.

　　While Opportunity has not found any signs of life, the presence of water means life is possible. “In everything we know about life on Earth, there is no example without liquid water,” Squyres said. “So water is important for the search for life on Mars.”