I ________ such a mistake again.

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－Gould you show me how to get to the nearest post office? -

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David said that ________ take this course again next term.

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Why not phone me earlier? You ________ the call half an hour ago.

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I guessed that he could have passed the examination, but ________.

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Since there's no bus and it's only fifteen minutes' walk, we ________.

[　　]

A．had better walk to home

B．have better walk home

C．had better walk home

D．had better to walk home

________ all the books ________ to the library before the term ends?

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Look! She is standing on the stage. She ________ her performance.

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One ought ________ for what one hasn't done.

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The room is locked. I think they ________ to the library.

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