could enhance
Regular verb: enhance - enhanced- enhanced

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could enhance
you could enhance
he could enhance
we could enhance
you could enhance
they could enhance 	I could be enhancing
you could be enhancing
he could be enhancing
we could be enhancing
you could be enhancing
they could be enhancing	I could have enhanced
you could have enhanced
he could have enhanced
we could have enhanced
you could have enhanced
they could have enhanced	I could have been enhancing
you could have been enhancing
he could have been enhancing
we could have been enhancing
you could have been enhancing
they could have been enhancing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't enhance
you couldn't enhance
he couldn't enhance
we couldn't enhance
you couldn't enhance
they couldn't enhance 	I couldn't be enhancing
you couldn't be enhancing
he couldn't be enhancing
we couldn't be enhancing
you couldn't be enhancing
they couldn't be enhancing	I couldn't have enhanced
you couldn't have enhanced
he couldn't have enhanced
we couldn't have enhanced
you couldn't have enhanced
they couldn't have enhanced	I couldn't have been enhancing
you couldn't have been enhancing
he couldn't have been enhancing
we couldn't have been enhancing
you couldn't have been enhancing
they couldn't have been enhancing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I enhance?
could you enhance?
could he enhance?
could we enhance?
could you enhance?
could they enhance? 	could I be enhancing?
could you be enhancing?
could he be enhancing?
could we be enhancing?
could you be enhancing?
could they be enhancing? 	could I have enhanced?
could you have enhanced?
could he have enhanced?
could we have enhanced?
could you have enhanced?
could they have enhanced? 	could I have been enhancing?
could you have been enhancing?
could he have been enhancing?
could we have been enhancing?
could you have been enhancing?
could they have been enhancing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I enhance?
couldn't you enhance?
couldn't he enhance?
couldn't we enhance?
couldn't you enhance?
couldn't they enhance? 	couldn't I be enhancing?
couldn't you be enhancing?
couldn't he be enhancing?
couldn't we be enhancing?
couldn't you be enhancing?
couldn't they be enhancing? 	couldn't I have enhanced?
couldn't you have enhanced?
couldn't he have enhanced?
couldn't we have enhanced?
couldn't you have enhanced?
couldn't they have enhanced? 	couldn't I have been enhancing?
couldn't you have been enhancing?
couldn't he have been enhancing?
couldn't we have been enhancing?
couldn't you have been enhancing?
couldn't they have been enhancing?