The maths problem is too difficult. ________ students in our class can work it out.

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You should close ________ eye while I'm having a checkup on the eyesight of one eye.

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Though smoking is known to be not good to one's health, many countries see ________ change in the number of smokers.

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Have a good rest, you need to ________ your energy (精力) for the tennis match this afternoon.

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Work harder, ________ you'll make greater progress.

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　　－How long does the exam usually ________?

　�。瑼bout one hour or two.

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　　－Do you know the story?

　　－Not really. ________ of us has read the story.

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We've planted ________ trees in the center of our city this year.

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With all these planes, now things can ________ everywhere much faster than before.

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　�。璂on't forget to come to my birthday party tomorrow?

　�。璤_______.

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