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This is the first time which I shall give you a lesson．

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I will never forget 1976 when was full of sadness．

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I still remember the days when I spent in Beijing．

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This is the book which he lost it yesterday．

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Apple eaters prove healthier than those don’t．

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Is this factory(which/that)you visited yesterday?

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The young couple walked through the street to the cafe．

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What he says doesn’t agree what he does．

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Milk doesn’t agree to me．

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The clock, my great-grandfather bought, is still in good order．