单选题Passage Four When
imaginative men turn their eyes towards space and wonder whether life exists in
any part of it, they may cheer themselves by remembering that life need not
resemble closely the life that exists on Earth. Mars looks like the only planet
where life like ours could exist, and even this is doubtful. But there may be
other kinds of life based on other chemistry, and they may multiply on Venus or
Jupiter. At least we cannot prove at present that they do not.
Even more interesting is the possibility that life on their planets may be in a
more advanced stage of evolution. Present-day man is in a peculiar and probably
temporary stage. His individual units retain a strong sense of personality. They
are, in fact, still capable under favorable circumstances of leading individual
lives. But man's societies are already sufficiently developed to have enormously
more power and effectiveness than the individuals have. It is
not likely that this transitional situation will continue very long on the
evolutionary time scale. Fifty thousand years from now man's societies may have
become so close-knit that the individuals retain no sense of separate
personality. Then little distinction will remain between the organic parts of
the multiple organisms and the inorganic parts (machines) that have been
constructed by it. A million years further on man and his machines may have
merged as closely as the muscles of the human body and the nerve cells that set
them in motion. The explorers of space should be prepared for
some such situation. If they arrive on a foreign planet that has reached an
advanced stage (and this is by no means impossible), they may find it being
inhabited by a single large organism composed of many closely cooperating
units. The units may be "secondary"—machines created millions
of years ago by a previous form of life and given the will and ability to
survive and reproduce. They may be built entirely of metals and other durable
materials. If this is the case, they may be much more tolerant of their
environment, multiplying under conditions that would destroy immediately any
organism made of carbon compounds and dependent on the familiar carbon
cycle. Such creatures might be relics of a past age, millions
of years ago, when their planet was favorable to the origin of life, or they
might be immigrants from a favored planet.
单选题
What does the word "cheer" (Para 1,) imply?
A. Imaginative men are sure of success in finding life on other
planets.
B. Imaginative men are delighted to find life on other planets.
C. Imaginative men are happy to find a different kind of life existing on
other planets.
D. Imaginative men can be pleased with the idea that there might exist
different forms of life on other planets.
【正确答案】
D
【答案解析】文章第一段“cheer…that life need not resemble closely…”，可知他们快活(cheer)的原因是外星球生命可以有不同的形式(different forms of life)。选D。
单选题
Humans on Earth today are characterized by ______.
A. their existence as free and separate beings
B. their capability of living under favorable conditions
C. their great power and effectiveness
D. their strong desire for living in a close-knit society
【正确答案】
A
【答案解析】第二段第三句“…a strong sense of personality”与A项内容相符。故A为正确答案。
单选题
According to this passage, some people believe that eventually ______.