could muff
Regular verb: muff - muffed- muffed

Affirmation 	
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I could muff
you could muff
she could muff
we could muff
you could muff
they could muff 	I could be muffing
you could be muffing
she could be muffing
we could be muffing
you could be muffing
they could be muffing	I could have muffed
you could have muffed
she could have muffed
we could have muffed
you could have muffed
they could have muffed	I could have been muffing
you could have been muffing
she could have been muffing
we could have been muffing
you could have been muffing
they could have been muffing	

Negation 	
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I couldn't muff
you couldn't muff
she couldn't muff
we couldn't muff
you couldn't muff
they couldn't muff 	I couldn't be muffing
you couldn't be muffing
she couldn't be muffing
we couldn't be muffing
you couldn't be muffing
they couldn't be muffing	I couldn't have muffed
you couldn't have muffed
she couldn't have muffed
we couldn't have muffed
you couldn't have muffed
they couldn't have muffed	I couldn't have been muffing
you couldn't have been muffing
she couldn't have been muffing
we couldn't have been muffing
you couldn't have been muffing
they couldn't have been muffing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I muff?
could you muff?
could she muff?
could we muff?
could you muff?
could they muff? 	could I be muffing?
could you be muffing?
could she be muffing?
could we be muffing?
could you be muffing?
could they be muffing? 	could I have muffed?
could you have muffed?
could she have muffed?
could we have muffed?
could you have muffed?
could they have muffed? 	could I have been muffing?
could you have been muffing?
could she have been muffing?
could we have been muffing?
could you have been muffing?
could they have been muffing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I muff?
couldn't you muff?
couldn't she muff?
couldn't we muff?
couldn't you muff?
couldn't they muff? 	couldn't I be muffing?
couldn't you be muffing?
couldn't she be muffing?
couldn't we be muffing?
couldn't you be muffing?
couldn't they be muffing? 	couldn't I have muffed?
couldn't you have muffed?
couldn't she have muffed?
couldn't we have muffed?
couldn't you have muffed?
couldn't they have muffed? 	couldn't I have been muffing?
couldn't you have been muffing?
couldn't she have been muffing?
couldn't we have been muffing?
couldn't you have been muffing?
couldn't they have been muffing?