CHANGE THE SENTENCES INTO THE PASSIVE(Xác định thành phần câu rồi mới chuyển)

21.They have to separate the rice from the husk.

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22.He shouldn’t do that silly thing.

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23.The boy operates that tape-recorder.

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24.They gave us a post card.

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25.The student cleaned the room every day.

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26.I had lost some of my books.

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27.We believe these boys to become better.

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28.The scientists found the problem.

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29.The cat pulls the pan into the sink.

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30.He gives her a novel about a love story.

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