Chuyển các câu sau sang câu bị động.
1, Mary is cutting a cake with a sharp knife
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2.They have provided the victims with food and clothing
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3. The children looked at the woman with a red hat
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4. People speak English in almost every corner of the world.
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5, You musn't use this machine after 5:30 p.m
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6. After class, one of the students always erases the chalk board
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