An atom of ordinary carbon has six protons and eight neutrons

试卷相关题目

• 1The radiocarbon dating technique is only about 40 years old

  A.Right

  B.Wrong

  C.Not mentioned

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• 2Nowadays many scientists depend on radiocarbon for dating age-old objects

  A.Right

  B.Wrong

  C.Not mentioned

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• 3There is always excitement at the Olympic Games when an athlete __breaks__ a record

  A.beats

  B.maintains

  C.matches

  D.tries

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• 4Obviously these people can be __relied on__ in a crisis.

  A.lived on

  B.depended on

  C.believed in

  D.joined in

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• 5The chairman __proposed__ that we stop the meeting.

  A.stated

  B.announced

  C.demanded

  D.suggested

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• 6Radar is used to determine the characteristics of radiocarbon.

  A.Right

  B.Wrong

  C.Not mentioned

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• 7Radiocarbon is reliable in dating an object back to at least 50，000 years.

  A.Right

  B.Wrong

  C.Not mentioned

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• 8When an organism dies， the C-14 in it begins to decay.

  A.Right

  B.Wrong

  C.Not mentioned

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• 9The half-life of C-14 is about 25，000 years.

  A.Right

  B.Wrong

  C.Not mentioned

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• 10On a clear night， people can see

  A.150 stars.

  B.hundreds of stars.

  C.one thousand stars.

  D.more than 14，000 stars.

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