首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
WATER AND LIFE ON MARS 1 The presence or absence of water has a direct bearing on the possibility of life on other planets. In
WATER AND LIFE ON MARS 1 The presence or absence of water has a direct bearing on the possibility of life on other planets. In
admin
2012-01-14
48
问题
WATER AND LIFE ON MARS
1 The presence or absence of water has a direct bearing on the possibility of life on other planets. In the nineteenth century, it was commonly accepted that life, perhaps even intelligent life, was widespread in the solar system, and Mars was an obvious target in the search for life. New photographic technology offered a way for astronomers to learn more about the red planet. In 1888, Italian astronomer Giovanni Schiaparelli produced images that showed a network of long, thin, dark lines crossing the surface of Mars. He called these features canali in Italian, which became "canals" or "channels" in English. The strange appearance of the canals suggested to some scientists that they had been formed artificially rather than naturally. The mystery deepened when Schiaparelli observed that many of the canals in the photographs were actually double.
2 Other photographic images of Mars revealed its seasonally changing polar ice caps and features that appeared to be ancient islands located in what was now a dry streambed. When the islands were first discovered, some scientists speculated that a thick water-laden atmosphere capable of generating heavy rains had once existed on Mars. However, others remained unconvinced of the presence of water. Then, in 1963, a team of astronomers obtained a good photographic plate of the near-infrared spectrum of Mars. The photograph showed that, faintly but definitely, water vapor lines could be seen. This photograph established that there really was water on Mars, though the amount was very small.
Today, the presence of water vapor in the Martian atmosphere is generally accepted, as is the belief that the atmosphere was once much denser than it is now, with a much greater abundance of water vapor.
3 The surface of Mars is dry today, but it does contain significant amounts of ice and signs that liquid water once flowed over the planet. All of the locations where evidence of water has been found are ancient, probably formed very early in Martian history. Data transmitted from spacecraft on Mars in 2004 have revealed that water was once common across a vast region of the planet, possibly as shallow lakes or seas that dried out and then filled up again. There are signs that the wind blew debris around during dry stages. These seas and lakes extended across hundreds of thousands of square miles, creating
habitable
conditions during long stretches of time billions of years ago.
4 Evidence of water includes the presence of various minerals known as evaporates, deposits left behind when liquid water turns to vapor. Small areas of mineral deposits have been found in Valles Marineris, a huge hole on Mars that is larger than the Grand Canyon on Earth. The minerals there contain water, so they had to be formed in the presence of water. Geologic research has also turned up clay and gypsum deposits that were formed by water in the soil. Rocks that clearly formed in water extend throughout 300 meters of layered materials in several locations across the Martian plains. The layers were built up over time, which means water was present, at least temporarily, for extended periods on ancient Mars.
5 Besides the ice packs at Mars’s poles, astronomers have discovered a frozen sea near its equator. This frozen sea is the size of the North Sea on Earth and appears similar to the ice packs on Antarctica. Scientists have also detected evidence of lava flows 20 million years ago as well as signs that some volcanoes may still be active. Several recently formed volcanic cones near Mars’s North Pole indicate that the planet’s core may interact with the surface, meaning there was both warmth and moisture in the recent pas-circumstances that might have supported life.
6 Liquid water is the key ingredient for life as we know it. Of all the other planets in the solar system, Mars is most like Earth. The fact that water existed on ancient Mars does not necessarily mean life ever emerged there; however, all of the available evidence does suggest that Mars meets all the requirements that are needed for life to exist.
Look at the four squares,A ,B, C, and D, which indicate where the following sentence could be added to the passage. Where would the sentence best fit?
Astronomers already knew that Mars had some kind of atmosphere because of the occasional presence of bright features that looked like clouds.
The presence or absence of water has a direct bearing on the possibility of life on other planets. A In the nineteenth century, it was commonly accepted that life, perhaps even intelligent life, was widespread in the solar system, and Mars was an obvious target in the search for life.B New photographic technology offered a way for astronomers to learn more about the red planet. In 1888, Italian astronomer Giovanni Schiaparelli produced images that showed a network of long, thin, dark lines crossing the surface of Mars.C He called these features canali in Italian, which became "canals" or "channels" in English. The strange appearance of the canals suggested to some scientists that they had been formed artificially rather than naturally.D The mystery deepened when Schiaparelli observed that many of the canals in the photographs were actually double.
选项
A、Square A.
B、Square B.
C、Square C.
D、Square D.
答案
B
解析
In the added sentence, Astronomers already knew that Mars had some kind of atmosphere logically follows Mars was an obvious target in the search for life in the previous sentence. (1.8)
转载请注明原文地址:https://kaotiyun.com/show/Z5yO777K
0
托福(TOEFL)
相关试题推荐
Youshouldspendabout20minutesonQuestions1-13,whicharebasedonReadingPassage1below.AverybriefhistoryoftimeTh
Trytoskimthetextbelowin30secondsanddecidewhichofthefollowingdescribesthemainideaofthetext.AItisimportan
AncientPeopleinSaharaOnOct.13,2000,PaulSereno,aprofessorfromtheUniversityofChicago,guidedateamofpalaeon
Lookatthefollowingopinionsordeedsandthelistofpeoplebelow.Matcheachopinionordeedwiththecorrectperson,A-
AccordingtoMrSingh,onwhichthingdomanypeoplemakesuperficialobservations?MrSinghsayshisgenerationcouldonlydre
Howdidthestudentgettheuniversityprospectus?Whatistheadvantageoftranslatingorcheckingtranslations?
SECTION3Questions21-30Questions21-24CompletethenotesonthepurposesofalessonplanusingNOMORETHANTHREEWORDSf
WhereisMrGarcialiving?【6】
Theprofessorsaysthatsuperhighways______.【29】
WhatisthepurposeofJaneandRick’smeetingwiththetutor?
随机试题
实验室管理者最主要的能力应该是
有关输卵管结扎术后病人的护理,正确的是
条件致病菌致病的条件为
社会工作者小齐计划采用个案研究方法对辖区内的空巢老人进行居家养老服务需求研究。从该研究方法的特点看,此项研究的结果可以()。
王某,男性,33岁,已婚,硕士研究生,单身在外工作(夫妻分居)。自我陈述:担心、紧张、烦躁不安、怀疑自己生病2年,自己就诊。2年前,由于工作应酬陪客人喝酒。可能是喝多的原因,我糊涂地与一个歌厅小姐发生了一次性关系,以后再未往来,也无其他类似经历,但我在
下列各项中,属于清洁能源的是()。
民事单方法律行为是指根据民事主体一方的意思表示即可成立的法律行为。依据上述定义,下列属于单方法律行为的是:
甲、乙两人同时从相距30千米的两地出发,相向而行。甲每小时走3.5千米,乙每小时走2.5千米。与甲同时、同地、同向出发的还有一只狗,每小时跑5千米,狗碰到乙后就回头向甲跑去,碰到甲后又回头向乙跑去……这只狗就这样往返于甲、乙之间直到二人相遇而止,则相遇时这
根据以下资料,回答下列问题。在2008年8月8日至24日奥运会期间,北京市的空气质量不仅天天达标,而且有10天达到一级,全面兑现了对奥运会空气质量的承诺。下图是2008年1一8月北京市大气质量检测情况,图中一、二、三、四级是空气质量等级,一级空气质量最好
--Wouldyoulikeanothercupofcoffee?--______.
最新回复
(
0
)