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         rior to 1965 geologists assumed 
         that the two giant rock plates meeting at 
         the San Andreas Fault generate heat 
  Line  through friction as they grind past each  
    (5)       other, but in 1965 Henyey found that 
  temperatures in drill holes near the 
  fault were not as elevated as had 
  been expected.  Some geologists 
  wondered whether the absence of 
   (10)       friction-generated heat could be 
  explained by the kinds of rock com- 
  posing the fault.  Geologists’ pre-1965 
  assumptions concerning heat gen- 
  erated in the fault were based on 
   (15)       calculations about common varieties of 
  rocks, such as limestone and granite; 
  but “weaker” materials, such as clays, 
  had already been identified in samples 
  retrieved from the fault zone.  Under 
   (20)       normal conditions, rocks composed of 
         clay produce far less friction than do 
         other rock types. 
         In 1992 Byerlee tested whether 
  these materials would produce friction 
   (25)       10 to 15 kilometers below the Earth’s 
  surface.  Byerlee found that when clay 
  samples were subjected to the thou- 
  sands of atmospheres of pressure 
  they would encounter deep inside the 
   (30)       Earth, they produced as much friction 
  as was produced by other rock types. 
  The harder rocks push against each 
         other, the hotter they become; in other 
  words, pressure itself, not only the 
   (35)       rocks’ properties, affects frictional 
  heating.  Geologists therefore won- 
  dered whether the friction between the 
  plates was being reduced by pockets 
  of pressurized water within the fault that 
  push the plates away from each other. 
   
   
  Q11:        
  The passage is primarily concerned with 
                 
  A.      evaluating a method used to test a particular scientific hypothesis 
  B.       discussing explanations for an unexpected scientific finding  
  C.      examining the assumptions underlying a particular experiment 
  D.      questioning the validity of a scientific finding 
  E.       presenting evidence to support a recent scientific hypothesis 
  我选了E. 请大家帮助!答案是B. 
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