could subvene
Regular verb: subvene - subvened- subvened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could subvene
you could subvene
she could subvene
we could subvene
you could subvene
they could subvene 	I could be subvening
you could be subvening
she could be subvening
we could be subvening
you could be subvening
they could be subvening	I could have subvened
you could have subvened
she could have subvened
we could have subvened
you could have subvened
they could have subvened	I could have been subvening
you could have been subvening
she could have been subvening
we could have been subvening
you could have been subvening
they could have been subvening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't subvene
you couldn't subvene
she couldn't subvene
we couldn't subvene
you couldn't subvene
they couldn't subvene 	I couldn't be subvening
you couldn't be subvening
she couldn't be subvening
we couldn't be subvening
you couldn't be subvening
they couldn't be subvening	I couldn't have subvened
you couldn't have subvened
she couldn't have subvened
we couldn't have subvened
you couldn't have subvened
they couldn't have subvened	I couldn't have been subvening
you couldn't have been subvening
she couldn't have been subvening
we couldn't have been subvening
you couldn't have been subvening
they couldn't have been subvening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I subvene?
could you subvene?
could she subvene?
could we subvene?
could you subvene?
could they subvene? 	could I be subvening?
could you be subvening?
could she be subvening?
could we be subvening?
could you be subvening?
could they be subvening? 	could I have subvened?
could you have subvened?
could she have subvened?
could we have subvened?
could you have subvened?
could they have subvened? 	could I have been subvening?
could you have been subvening?
could she have been subvening?
could we have been subvening?
could you have been subvening?
could they have been subvening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I subvene?
couldn't you subvene?
couldn't she subvene?
couldn't we subvene?
couldn't you subvene?
couldn't they subvene? 	couldn't I be subvening?
couldn't you be subvening?
couldn't she be subvening?
couldn't we be subvening?
couldn't you be subvening?
couldn't they be subvening? 	couldn't I have subvened?
couldn't you have subvened?
couldn't she have subvened?
couldn't we have subvened?
couldn't you have subvened?
couldn't they have subvened? 	couldn't I have been subvening?
couldn't you have been subvening?
couldn't she have been subvening?
couldn't we have been subvening?
couldn't you have been subvening?
couldn't they have been subvening?