Which of the following best expresses the main idea of this passage、

试卷相关题目

• 1Which of the following statements is true、

  A.Allergens are usually harmful substances．

  B.Antigens can trigger an immune response．

  C.People with antigens do not suffer from obvious responses．

  D.There is no difference between an antigen and an allergen．

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• 2How do the immune cells recognize an antigen as“foreign”or“nonself”、

  A.Through an allergic response．

  B.Through blood type．

  C.Through characteristic shapes on the antigen surface．

  D.Through fine hairs protruding from the antigen surface．

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• 3The immune cells and other cells in the body coexist peaceably in a state known as

  A.self-tolerance

  B.balance

  C.harmony

  D.tolerance

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• 4What is used to describe the communication network consisting of cells in the immune system、

  A.The immune system’s memory．

  B.Immune troops eliminating intruders．

  C.Bees flying around a hive．

  D.A sea of microbes．

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• 5It is good advice for most people to________.

  A.stay up till the early hours of the morning

  B.sleep enough to bring most refreshment

  C.rebuild memories stored during the day

  D.store memories in the brain

  E.get up quite early

  F.keep away from coffee in the evening

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• 6People buy cell phones for the following reasons EXCEPT that

  A.they’re popular．

  B.they’re useful．

  C.they’re cheap．

  D.they’re convenient．

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• 7The word“detected”in paragraph 3 could be best replaced by

  A.cured．

  B.removed．

  C.discovered

  D.caused

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• 8The salesman retired young because

  A.he disliked using mobile phones．

  B.he was tired of talking on his mobile phone．

  C.his employer’s doctor persuaded him to．

  D.he couldn’t remember simple tasks．

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• 9On the safety issue of mobile phones，the manufacturing companies

  A.deny the existence of mobile phone radiation．

  B.develop new technology to reduce mobile phone radiation．

  C.try to prove that mobile phones are not harmful to health．

  D.hold that the amount of radiation is too small to worry about．

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• 10The writer’s purpose of writing this article is to advise people

  A.to buy mobile phones．

  B.to use mobile phones less often．

  C.to update regular phones．

  D.to stop using mobile phones．

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