Convert following active sentences into passive forms
1. How many languages do they speak in Canada?
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2. Did Mary buy this beautiful dress?
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3. Are you going to help her solve that problem?
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4. Have you turned off the air-conditioner?
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5. When will you hand in the required assignment?
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6. How many times have i told you to keep silent in class?
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7. Should i send a complaint letter to the mayor?
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8. Had you come to any conclusions before we came?
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