Chuyển các câu au sang câu bi động

Bài tập viết câu PASSIVE
22. Nam should help us.
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23. Nam must help them.
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24. Nam used to help you.
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25. Nam has to help Lan.
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26. Nam has to help the children.
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27. Nam is going to help Lan.
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28. Nam is going to help the old people.
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29. Nam helps Lan with her homework every day.
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30. Nam met Lan at the airport last Saturday.
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31. Nam will meet Lan at the airport tomorrow.
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32. Nam has helped Lan with her homework since 2 o'clock.
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