Black holes ________ not be seen directly，so determining the number of them is a tough task．

试卷相关题目

• 1The climbers ______ reach the top of the mountain, but because of the sudden snowstorm, they ______ come down．

  A.could ;weren't able to

  B.were able to ;couldn't

  C.could ;couldn't

  D.were possible to ;couldn't

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• 2Had she been older, she ________ it better.

  A.had done

  B.might have done

  C.might do

  D.would do

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• 3No one ________ into the cave without light.

  A.dares go

  B.dare go

  C.dare to go

  D.dared going

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• 4How much money, ________, have you paid for this flat?

  A.I can ask

  B.I must ask

  C.shall I ask

  D.may I ask

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• 5This piece of information has not been made public yet．You ______ never mention it to anyone else．

  A.might

  B.must

  C.could

  D.will

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• 6I am surprised that he ________ to help me when I needed it most.

  A.should refuse

  B.would have refused

  C.should have refused to

  D.may have refused

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• 7Our holidays were ruined by the weather; ______ have stayed at home．

  A.it may be as well

  B.it was just as well we

  C.we might just as well

  D.we might do as well as we

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• 8Since it is already midnight, we ________.

  A.had better leaving

  B.ought to have leave

  C.should take our leave

  D.might as well leave

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• 9---- Daddy ,can you buy me a new MP3 when you go to Beijing? ---- You ____ get one if you are admitted to a key middle school

  A.could

  B.shall

  C.may

  D.can

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• 10The horses ought ________ hours ago by raisers.

  A.to have been fed

  B.to feed

  C.to be fed

  D.to have fed

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