When men spend long periods in space how will they protect themselves、

试卷相关题目

• 1The spacemen were worried about solar flares when they were

  A.crossing the Van Allen belts.

  B.setting up a moon base.

  C.exploring the surface of the moon.

  D.waiting in the command modul

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• 2Scientists have fixed a safety level of

  A.10 rems per year.

  B.60 rems per year.

  C.100 millirems per year.

  D.5 rems per hour.

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• 3The worst hazard for spacemen is

  A.meteors.

  B.heat.

  C.radiation.

  D.gas.

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• 4In sentense 2,“speculated on”(line 4)means

  A.suspected

  B.expected

  C.engaged in buying and selling

  D.considered

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• 5The passage says that until recently scientists disagreed with the idea _____ .

  A.that there are mysterious forces in the universe.

  B.that man cannot discover what forces“really” are.

  C.that there are selfevident principles.

  D.that we can discover why things behave as they do.

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• 6Which of the following is true、

  A.The grandchildren of astronauts are deformed.

  B.The children of astronauts have damaged sex organs.

  C.Radiation damage may show only in later generations.

  D.Radiation does not seem to be very harmful.

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