55.Obligation
DUTY
INTERDICTION
ABSENCE OF OBLIGATION
He must do this.
1
2
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4
He is supposed to do this. 
He has to do this. 
He mustn’t do this. 
He isn’t supposed to do this. 
He isn’t allowed to do this. 
5
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7
He doesn’t have to do this. 
He doesn’t need to do this. 
He needn’t do this. 
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