could cancel
Regular verb: cancel - cancelled- cancelled

Affirmation 	
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I could cancel
you could cancel
she could cancel
we could cancel
you could cancel
they could cancel 	I could be cancelling
you could be cancelling
she could be cancelling
we could be cancelling
you could be cancelling
they could be cancelling	I could have cancelled
you could have cancelled
she could have cancelled
we could have cancelled
you could have cancelled
they could have cancelled	I could have been cancelling
you could have been cancelling
she could have been cancelling
we could have been cancelling
you could have been cancelling
they could have been cancelling	

Negation 	
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I couldn't cancel
you couldn't cancel
she couldn't cancel
we couldn't cancel
you couldn't cancel
they couldn't cancel 	I couldn't be cancelling
you couldn't be cancelling
she couldn't be cancelling
we couldn't be cancelling
you couldn't be cancelling
they couldn't be cancelling	I couldn't have cancelled
you couldn't have cancelled
she couldn't have cancelled
we couldn't have cancelled
you couldn't have cancelled
they couldn't have cancelled	I couldn't have been cancelling
you couldn't have been cancelling
she couldn't have been cancelling
we couldn't have been cancelling
you couldn't have been cancelling
they couldn't have been cancelling	

Interrogative form 	
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could I cancel?
could you cancel?
could she cancel?
could we cancel?
could you cancel?
could they cancel? 	could I be cancelling?
could you be cancelling?
could she be cancelling?
could we be cancelling?
could you be cancelling?
could they be cancelling? 	could I have cancelled?
could you have cancelled?
could she have cancelled?
could we have cancelled?
could you have cancelled?
could they have cancelled? 	could I have been cancelling?
could you have been cancelling?
could she have been cancelling?
could we have been cancelling?
could you have been cancelling?
could they have been cancelling? 	

Interro-negative form 	
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couldn't I cancel?
couldn't you cancel?
couldn't she cancel?
couldn't we cancel?
couldn't you cancel?
couldn't they cancel? 	couldn't I be cancelling?
couldn't you be cancelling?
couldn't she be cancelling?
couldn't we be cancelling?
couldn't you be cancelling?
couldn't they be cancelling? 	couldn't I have cancelled?
couldn't you have cancelled?
couldn't she have cancelled?
couldn't we have cancelled?
couldn't you have cancelled?
couldn't they have cancelled? 	couldn't I have been cancelling?
couldn't you have been cancelling?
couldn't she have been cancelling?
couldn't we have been cancelling?
couldn't you have been cancelling?
couldn't they have been cancelling?