When an airplane flies too high，___________.

试卷相关题目

• 1What color is the sky、

  A.It iS blue．

  B.It iS white．

  C.It is grey．

  D.It has no color．

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• 2What is the final purpose of Project BudBurst、

  A.To study when plants will have their first buds．

  B.To find out the types of plants in the neighborhood．

  C.To collect life cycle data on a variety of common plants from across the United States．

  D.To investigate how plants and animals will respond as the climate changes．

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• 3What is NOT true of Project BudBurst、

  A.Only experts can participate in it．

  B.Everybody can participate in it．

  C.It collects life cycle data on a variety of common plants．

  D.It has its own website．

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• 4In"All that，s needed to become one…(paragraph2)"，what does the word"one"stands for、

  A.a citizen journalist

  B.a citizen scientist

  C.a scientist

  D.a citizen

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• 5What are citizen scientists asked to do、

  A.To develop a specific research interest and become professional scientists．

  B.To send their research observations to a professional database．

  C.To increase their knowledge about climate change．

  D.To keep a record of their research observations．

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• 6A rocket can fly to the moon because__________

  A.it looks like a balloon．

  B.it is much lighter than an airplane．

  C.it doesn't have wings．

  D.it works like an untied balloon．

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• 7Which of the following statements about a rocket is NOT true、

  A.It can fly when there is no air．

  B.It can fly without wings．

  C.It is made of strong metal．

  D.It is propelled by burning gas inside it．

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• 8A rocket is pushed up into the air when__________

  A.hot gas rushes out of its head．

  B.it is powered by gas．

  C.hot gas rushes out of its bottom．

  D.hot gas rushes out of its neck．

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