阅读理解
For centuries, explorers have risked their lives venturing into the unknown for reasons that were to varying degrees economic and nationalistic. Columbus went west to look for better trade routes to the Orient and to promote the greater glory of Spain. Lewis and Clark journeyed into the American wilderness to find out what the U.S. had acquired when it purchased Louisiana, and the Appolo astronauts rocketed to the moon in a dramatic show of technological muscle during the cold war.
Although their missions blended commercial and political-military imperatives, the explorers involved all accomplished some significant science by going where no scientists had gone before.
Today Mars looms (隐约出现) as humanity''s next great terra incognita (未探明之地). And with doubtful prospects for a short-term financial return, with the cold war a rapidly fading memory and amid a growing emphasis on international cooperation in large space ventures, it is clear that imperatives other than profits or nationalism will have to compel human beings to leave their tracks on the planet''s reddish surface. Could it be that science, which has long played a minor role in exploration, is at last destined to take a leading role? The question naturally invites a couple of others: Are there experiments that only human could do on Mars7 Could those experiments provide insights profound enough to justify the expense of sending people across interplanetary space.*
With Mars the scientific stakes are arguably higher than they have ever been. The issue of whether life ever existed on the planet, and whether it persists to this day, has been highlighted by mounting evidence that the Red Planet once had abundant stable, liquid water and by the continuing controversy over suggestions the bacterial fossils rode to Earth on a meteorite (陨石) from Mars. A more conclusive answer about life on Mars, past or present, would give researchers invaluable data about the range of conditions under which a planet can generate the complex chemistry that leads to life. If it could be established that life arose independently on Mars and Earth, the finding would provide the first concrete clues in one of the deepest mysteries in all of science: the prevalence of life in the universe.
单选题
According to the passage, the chief purpose of explorers in going to unknown places in the past was ___________.
【正确答案】
D
【答案解析】辨认事实题。题目询问根据文章的观点，在过去探险者进入未探明之地的主要目的。根据文章第1段第1句“For centuries，explorers have risked their lives venturing into the unknown for reasons that were to varying degrees economic and nationalistic(几个世纪以来，出于或多或少的经济原因及国家利益的考虑，探险家冒着生命危险深入到未知领域)”，D项与文章所给的意思一致，故而正确。
单选题
At present, a probable inducement for countries to initiate large-scale space ventures is ___________.
【正确答案】
B
【答案解析】推断题。题目询问目前驱动各个国家进行大规模太空冒险的可能的动机。在文章第3段作者提到“it is clear that imperatives other than profits or nationalism will have to compel human beings to leave their tracks on the planet''s reddish surface。Could it be that science，which has long played s minor role in exploration，is at last destined to take a leading role?(很显然，推动人类在该星球微红表面上留下足迹的必将是除了利益和国家主义之外的别的需要。那么，在以往探险中一直扮演次要角色的科学这一次终于注定是主角了吗?)”，由此可推断，在目前，人们的太空冒险活动是一种科学研究。因此，B项与文章的意思相符。
单选题
What is the main goal of sending human missions to Mars?
【正确答案】
A
【答案解析】辨认事实题。题目询问将人们送上火星的主要目的。根据第4段“The issue of whether life ever existed on the planet，and whether it persists to this day，has been highlighted by mounting evidence that the Red Planet once had abundant stable，liquid water and by the continuing controversy over suggestions the bacterial fossils rode to Earth on a meteorite(陨石)from Mars(越来越多的证据表明，这颗红色行星曾有过充足、稳定的液态水；而关于从火星落到地球上的陨石里含有细菌化石的意义，人们也一直在争论不休)”，由此推断人们探测火星的目的就是想解开此谜。因此，A项与文章所陈述的意思相符，故而正确。
单选题
By saying "With Mars the scientific stakes are arguably higher than they have ever been" ( Line 1, Para. 4 ), the author means that ___________.
【正确答案】
B
【答案解析】推断题。题目询问作者说：“With Mars the scientific stakes arc arguably his her than they have ever been”这句话的含意是__________。根据字面翻译，这句话的意思是“探测火星的科技回报可能比其他任何一次探险都高。”在文章最后一段，作者又提到“A more conclusive answer about life on Mars，past or present，would give researchers invaluable data about the range of conditions under which a planet Can generate the complex chemistry that leads to life. If it could be established that life arose independently on Mars and Earth， the finding would provide the first concrete clues in one of the deepest mysteries in all of science：the prevalence of life in the universe(就火星上过去或现在的生命问题提供一个更具结论性的答案，将会给研究者提供宝贵的资料，使他们了解在何种条件下，一个行星体能够产生复杂的化学反应，导致生命的出现。如果人们能够得出生命能够独立地出现于火星和地球的判断，那么这个发现将会为一切科学中最神秘的问题，即宇宙间生命何以普遍存在的问题，第一次提供具体线索)”，由此可推测火星探测的回报将是非常丰厚的。因此，B项与文章的意思相符合。
单选题
The passage tells us that proof of life on Mars would ___________.
【正确答案】
C
【答案解析】辨认事实题。题目询问文章告诉我们火星上有生命的证据表明了___________。根据文章最后一段“A more conclusive answer about life on Mars，past or present，would give researchers invaluable data about the range of conditions under which a planet can generate the complex chemistry that leads to life (就火星上过去或现在的生命问题提供一个更具结论性的答案，将会给研究者提供宝贵的资料，使他们了解在何种条件下，一个行星体能够产生复杂的化学反应，导致生命的出现)”，因此，只有C项与文章的意思相符，故而正确。