Nobody knows how people first came to these islands. They ________ from South America on rafts.

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－Could I borrow your dictionary?

－Yes, of course you ________.

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－May I stop here?

－No, you ________.

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Please open the window, ________?

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I thought you ________ like something to read, so I have brought you some books.

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If Alice ________ this afternoon, the meeting should be put off.

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－Would you come and join them?

－I wish I ________. But I am busy at this moment.

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We ________ the manager, but no one ________ his telephone number.

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A．could have called;knew

B．could have called;had known

C．could call;had known

D．could call; knew

We ________ the work so early without your help.

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Isn't it strange that the lazy boy ________ pass the exam?

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