[ Modal Verbs ]
I’m sure that they had practiced hard for the games as they won a lot of medals.
A. They couldn’t have practiced hard for the games as they won a lot of medals
B. They must have practiced hard for the games as they won a lot of medals
C. They shouldn’t have practiced hard for the games as they won a lot of medals
D. They might have practiced hard for the games as they won a lot of medals.

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A. When
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John bought a boat .. costs thirty thousand dollars.
A. which
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