单选题
For centuries, explorers have risked their lives
venturing into the unknown for reasons that were to varying degrees economic and
nationalistic (国家主义的). 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 simply by going
where no scientists had gone before. Today Mars looms (隐约出现的)
as humanity's next great terra incognita (未探明之地). And with growing emphasis on
international cooperation in large space ventures, it is clear that imperatives
(需要，必要) 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 humans could do on Mars? 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 that 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 ______.
A. to display their country's military might
B. to accomplish some significant science
C. to find new areas for colonization
D. to pursue commercial and state interests
【正确答案】
D
【答案解析】[解析] 细节题。本题问及过去探索未知宇宙的主要目的是什么。根据第一段主题句...for reasons that were to varying degrees economic and nationalistic(其原因在不同程度上都是经济的和国家主义的)可以选D，commercial和state分别与economic和nationalistic对应。
单选题
At present, a probable inducement (诱因) for countries to initiate
large-scale space ventures is ______.
A. international cooperation
B. nationalistic reasons
C. scientific research
D. long-term profits
【正确答案】
C
【答案解析】[解析] 细节题。问及现在促使各国进行大规模空间探索的可能原因。答案在第三段it is clear that imperatives other than profits or nationalism will...和Could it be that science...is at last destined to take a leading role?所以选C。国际合作不是原因，不能说过去为了国家利益，现在为了国际合作，逻辑上不通。
单选题
What is the main goal of sending human missions to Mars?
A. To find out if life ever existed there.
B. To see if humans could survive there.
C. To prove the feasibility of large-scale space ventures.
D. To show the leading role of science in space exploration.