补全短文 U.S. Scientists Confirm Water on Mars
NASA1 scientists said that Mars was covered once by vast lakes， flowing rivers and a variety of other wet environments that had the potential to support life.
Laboratory tests aboard NASAs Phoenix Mars Lander2 have identified water in a soil sample; the landers robotic arm delivered the sample Wednesday to an instrument that identifies vapors produced by the heating of samples.
"We have water，" said William Boynton of the University of Arizona， lead scientist for the Thermal and Evolved-Gas Analyzer3， or TEGA. "This is the first time Martian water has been touched and tasted. "
The robotic arm is a critical part of the Phoenix Mars mission. It is needed to trench" into the icy layers of northern polar Mars and deliver samples to instruments that will analyze what Mars is made of， what its water is like， and whether it is or has ever been a possible habitat for life.
The soil sample came from a trench approximately 2 inches deep. When the robotic arm first reached that depth， it hit a hard layer of frozen soil. Two attempts to deliver samples of icy soil on days when fresh material was exposed were foiled when the samples became stuck inside the scoop. Most of the material in Wednesdays sample had been exposed to the air for two days， letting some of the water in the sample vaporize away and making the soil easier to handle.
"Mars is giving us some surprises，" said Phoenix principal investigator Peter Smith of the University of Arizona. "Were excited because surprises are where discoveries come from. One surprise is how the soil is behaving. The ice-rich layers stick to the scoop when poised in the sun above the deck， different from what we expected， from all the Mars simulation testing weve done so far. "
Since landing on May 25， Phoenix has been studying soil with a chemistry lab， TEGA， a microscope， a conductivity probe and cameras. The science team is trying to determine whether the water ice ever thaws enough to be available for biology and if carbon-containing chemicals and other raw materials for life are present.
The mission is examining the sky as well as the ground. A Canadian instrument is using a laser beam to study dust and clouds overhead.
"Its a 30-watt light bulb giving us a laser show on Mars，" said Victoria Hipkin of the Canadian Space Agency.
A full-circle， color panorama of Phoenixs surroundings also has been completed by the spacecraft.
"The details and patterns we see in the ground show an ice-dominated terrain as far as the eye can see，" said Mark Lemmon of Texas A & M University， lead scientist for Phoenixs Surface Stereo Imager4 camera. "They help us plan measurements were making within reach of the robotic arm and interpret those measurements on a wider scale. "
词汇：
foil v. 挫败，使成泡影 conductivity n. 传导陡，导电胜
scoop n. 铲斗 thaw v. 融化，融解
vaporize v. 使蒸发，使汽化 panorama n. 全貌，全景图
注释：
1.NASA：National Aeronautics and Space Administration(美国国家航空航天局)的缩写。NASA总部设在华盛顿哥伦比亚特区，是美国政府系统中的航空航天科研机构，负责组织和协调美国航空航天的研究工作并提供咨询。
2.Phoenix Mars Lander：凤凰号火星登陆器。其使命是探测火星地表下的冰层，分析冰层是否曾经融化产生液态水，并计划检测火星土壤是否含有生命存活的有机物。
3.Thermal and Evolved—Gas Analyzer：热力与先进气体分析仪
4.Stereo Imager：立体图像
练习：
1. What was discovered by NASAs Phoenix Mars Lander on Mars?
A)Vast lakes.
B)Flowing rivers.
C)Water in a soil sample.
D)Living things.
2. Why did the first two attempts to deliver samples fail?
A)The sample vaporized away.
B)Fresh material was exposed to the air.
C)The samples got stuck inside the scoop.
D)The robotic arm hit a hard rock.
3. Which one of the following statements is NOT meant by the writer?
A)Scientists have been trying to break the ice-rich layers of soil on Mars.
B)Scientists have been surprised by how the soil on Mars behaves.
C)Scientists have been trying to fend out if there is life supporting material on Mars.
D)Scientists have been trying to know if water ice will melt.
4. Where are the scientists involved in the research from?
A)They are from America.
B)They are from Canada.
C)They are from both America and Canada.
D)They are from neither America nor Canada.
5. Which of the following do you think is the best description of Phoenixs Surface Stereo Imager Camera， according to your understanding of the passage?
A)It imitates human vision and is able to capture three-dimensional images.
B)It imitates human voice and is able to record slight sounds while taking photos.
C)It takes clear photos that show every detail of the object.
D)It is this particular type of camera that can take wide angle pictures.
答案与题解：
1.C 短文的第一段告诉我们，NASA科学家曾经说过，火星上有广阔的湖泊，流动的河流，以及可能有支撑生命的潮湿环境。但这些只是科学家的假设，不是NASA’S Phoenix Mars Lander的发现，所以只有C是正确选择。
2.C 短文第五段的第三句提供了答案。
3. A 第六段的第三句所述内容说明B是作者想要表达的意思，第七段的最后一句所述内容说明C和D也是作者想要表达的意思。文章里没有A所表述的内容。
4.C 短文的第八和第九段提到了加拿大宇航局的科学家为凤凰号的火星探索提供了激光设备。
5. A短文最后一段的第一句：A full—circle，color panorama of Phoenix’S surroundings also has been completed…告诉我们，使用这种照相机可以拍摄全景照片。panorama：全景，全景摄影。
