Reason (1)
nUse the passive voice  to emphasize the action not the person who performs it.
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§Notice that:
n The object of the sentence  replaces the subject.
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nExample:
n1-  Farmers grow grapes in the North.(Present Active)
n2- Grapes are grown in the North.(Present Passive)
n3- Grapes were grown in the North.(Past Passive)
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