四级听力

    即将进入2015年12月英语 四六级考试冲刺复习阶段，听力部分占据大量分值，但却是考试的重难点之一，冲刺备考阶段就来 四六级考试网练习一下英语 四级听力题吧。

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　　NASA: Strong Evidence of Liquid Water on Mars

　　Scientists have found strong evidence of salt wateron the planet Mars, the U.S. space agency NASAannounced Monday.

　　NASA has found lines of "hydrated" salt minerals onMars. Scientists say these minerals would requireliquid water to be created. And where there's liquid water, they say, there could be life.

　　Jim Green is the director of planetary science at NASA Headquarters. He said during a newsconference that "today, we are revolutionizing our understanding of this planet."

　　Doug McCuistion is the former head of NASA's Mars program. He told the Boston Herald that "ifthey are announcing that they have found easily accessible, freely flowing liquid water underthe surface ... that has massive implications both for the potential for life on that planet andsustainability of humans."

　　NASA has found evidence of water on Mars in the past. In March, NASA said there was oncemore water on Mars than in Earth's Arctic Ocean. They say more than four billion years ago,Mars was covered with water 137 meters deep. But nearly all of it has since evaporated intospace.

　　1.evidence 证据;证明;迹象

　　A transcript of the tapes was presented as evidencein court.

　　录音带的文字记录被作为证据在法庭上出示。

　　2.hydrated 水合的;含水的

　　Plain water is fine for staying hydrated during the week.

　　一周之中白开水可以很好保持水化的。

　　3.planetary 行星的

　　One of the most remarkable features of the solar system is the variety of planetaryatmospheres.

　　太阳系的最重要特徵之一，就是不同的行星有各不相同的大气模式。

　　4.evaporated 蒸发;消失

　　The sun evaporated some of the water, leaving land.

　　太阳把一部分水蒸发了，于是土地露了出来。

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