Liquid water only exists

试卷相关题目

• 1The half-life of C-14 is about 25，000 years.

  A.Right

  B.Wrong

  C.Not mentioned

  开始考试点击查看答案
• 2The C-14 in an organism begins to decay when it dies

  A.Right

  B.Wrong

  C.Not mentioned

  开始考试点击查看答案
• 3Radiocarbon is reliable in dating an object back to at least 50，000 years.

  A.Right

  B.Wrong

  C.Not mentioned

  开始考试点击查看答案
• 4Radar is used to determine the characteristics of radiocarbon

  A.Right

  B.Wrong

  C.Not mentioned

  开始考试点击查看答案
• 5An atom of ordinary carbon has six protons and eight neutrons

  A.Right

  B.Wrong

  C.Not mentioned

  开始考试点击查看答案
• 6The total quantity of water on Earth

  A.remains almost unchanged.

  B.has greatly increased in recent years.

  C.is decreasing constantly.

  D.is affected by global warming.

  开始考试点击查看答案
• 7Most of the fresh water on Earth

  A.is stored underground.

  B.is in the form of ice at the Poles and on mountains.

  C.is found in rivers and lakes.

  D.comes from the rain.

  开始考试点击查看答案
• 8The word “fraction” in the second paragraph means

  A.a very small amount.

  B.a large area.

  C.an important system.

  D.a major source of information

  开始考试点击查看答案
• 9There is more of rainfall

  A.over the mountains than over the rivers.

  B.over the rivers than over the mountains

  C.over the oceans than over the lan

  D.D.over the land than over the oceans.

  开始考试点击查看答案
• 10What is responsible for processing the information sent by your eyes？

  A.The magnetic system in the brain.

  B.The central part of the heart.

  C.Oxygen-rich bloo

  D.D.Neurons in the brain.

  开始考试点击查看答案