2. 外语
  3. Humans are forever forgetting that they can’ t control nature. Exactly 20 years ago, a Time magazine cover story announced that

Humans are forever forgetting that they can’ t control nature. Exactly 20 years ago, a Time magazine cover story announced that

admin2010-01-07  57
问题    Humans are forever forgetting that they can’ t control nature. Exactly 20 years ago, a Time magazine cover story announced that scientists are on the verge of being able to predict the time, place and even the size of earthquakes. "The people of quake-ravaged Kobe learned last week how wrong that assertion was."
   None of the methods conceived two decades ago has yet to discover a uniform warning signal that preceded all quakes, let alone any sign that would tell whether the coming tremor is mild or a killer. Earthquake formation can be triggered by many factors, says Hiroo Kanamori, a seismologist at the California Institute of Technology. So, finding one all-purpose warning sign is impossible. One reason: Quakes start deep in the earth, so scientists can’ t study them directly. If a quake precursor were found, it would still be impossible to warn humans in advance of all dangerous quakes. Places like Japan and California are riddled with hundreds, if not thousands, of minor faults.
   Prediction would be less important if scientists could easily build structures to withstand tremors. While seismic engineering has improved dramatically in the past 10 to 15 years, every new quake reveals unexpected weaknesses in "quake-resistant" structures, says Terry Tullis, a geophysicist at Brown University. In Kobe, for example, a highway that opened only last year was damaged. In the Northridge earthquake, on the other hand, well-built structures generally did not collapse.
   A recent report in science adds yet more anxiety about life on the faulty lines. Researchers ran computer simulations to see how quake-resistant buildings would fare in a moderate-size tremor, taking into account that much of a quakes energy travels in a large "pulse" of focused shaking. The results: Both steel-frame buildings and buildings that sit on insulating rubber pads suffered severe damage.
   More research will help experts design stronger structures and possibly find quake precursors. But it is still a certainty that the next earthquakes will prove once again that every fault cannot be monitored and every highway cannot be completely quake-proofed.  
One of the chief difficulties in accurate earthquake warning is that ______ .
选项 A、earthquakes may take place in anywhere possible
B、earthquakes may happen at any unexpected moment
C、most earthquakes take place simultaneously and unexpectedly
D、the occurrence of earthquakes involves too many unforeseen factors
答案D
解析 见文章第二段中间。
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