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  3. The unknown pervades the universe. That which people can see, with the aid of various sorts of telescope, accounts for just 4% o

The unknown pervades the universe. That which people can see, with the aid of various sorts of telescope, accounts for just 4% o

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问题     The unknown pervades the universe. That which people can see, with the aid of various sorts of telescope, accounts for just 4% of the total mass. The rest, however, must exist. Without it, galaxies would not survive and the universe would not be gently expanding, as witnessed by astronomers. What exactly constitutes this dark matter and dark energy remains mysterious, but physicists have recently uncovered some more clues, about the former, at least.
    One possible explanation for dark matter is a group of subatomic particles called neutrinos. Neutrinos are thought to be the most abundant particles in the universe. According to the Standard Model, the most successful description of particle physics to date, neutrinos come in three varieties, called "flavors". Again, according to the Standard Model, they are point-like, electrically neutral and massless. But in recent years, this view has been challenged, as physicists realized that neutrinos might have mass.
    The first strong evidence came in 1998, when researchers at an experiment, based in Japan, showed that muon neutrinos produced by cosmic rays hitting the upper atmosphere had gone missing by the time they should have reached an underground detector. Its operators suspect that the missing muon neutrinos had changed flavor, becoming electron neutrinos or-more likely-tau neutrinos. Theo- ry suggests that this process, called oscillation, can happen only if neutrinos have mass.
    Over the coming months and years, researchers hope to produce the most accurate measurements yet. The researchers created a beam of muon neutrinos first. On the other side of the target sat a particle detector that monitored the number of muon neutrinos leaving. The neutrinos then travelled 750km (450 miles) through the Earth to a detector in a former iron mine in Soudan, Minnesota. Researchers then were able to confirm that a significant number of muon neutrinos had disappeared-that is, they had changed flavor. While their mass is so small that neutrinos cannot be the sole constituent of dark matter, they have an advantage in that they are at least known to exist.
    The same cannot be said for sure of another possible form of dark matter being studied by a group of physicists in Italy. If the result continues to withstand scrutiny, it would appear to be evidence for an exotic new sort of fundamental particle, known as an axion, which could also be a type of dark matter.
Which one of the following statements is true about axion?
选项 A、It is known for sure to exist although not enough evidence is available.
B、It is another possible constituent of dark matter.
C、The search for hypothetical particle has failed so far.
D、If successful, experiment will prove it to be the sole form of dark matter.
答案B
解析 细节题；axion对于绝大多数考生来说是生僻的词汇，但恰好可以帮助我们迅速定位到原文的最后一段。A和D选项都需要我们结合前面一段的论述进行判断，因为这一段落中的the same cannot be said for sure of这样的表达告诉我们前面的信息对这里的判断仍然具有价值，而比较阅读之后我们发现，A选项的for sure以及D选项的sole form都和原文表达的意思截然相反。C选项的判断没有原文信息可以支持，而B选项的表达是严谨的，这里对于axion的探索是建立在假设基础上的一种逐步论证的过程，此处的possible很好地体现了这种在结果没有最终确定之前严谨的科学态度，和整个文章属于理科文章的表述风格是一致的，也是我们这个题目的正确选项。
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