He ________ great progress in the last two years .

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About 10, 000 years ago, the world's population ________ very small.

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Many ________ trees are planted in Shanbei . It is a‘Green Wall’ of trees .

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Today we are going to learn ________ lesson.

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________ he did the same thing in the office so he was tired of his job.

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Mrs Black was busy ________ clothes yesterday .

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She told me that she would come to see me when she ________ China again .

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Tom said his grandma was arriving that evening and he ________ her at the station .

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How often do you write to your uncle ? ________

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________ foreign friends come to visit China every year.

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