could overtighten
Regular verb: overtighten - overtightened- overtightened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could overtighten
you could overtighten
he could overtighten
we could overtighten
you could overtighten
they could overtighten 	I could be overtightening
you could be overtightening
he could be overtightening
we could be overtightening
you could be overtightening
they could be overtightening	I could have overtightened
you could have overtightened
he could have overtightened
we could have overtightened
you could have overtightened
they could have overtightened	I could have been overtightening
you could have been overtightening
he could have been overtightening
we could have been overtightening
you could have been overtightening
they could have been overtightening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't overtighten
you couldn't overtighten
he couldn't overtighten
we couldn't overtighten
you couldn't overtighten
they couldn't overtighten 	I couldn't be overtightening
you couldn't be overtightening
he couldn't be overtightening
we couldn't be overtightening
you couldn't be overtightening
they couldn't be overtightening	I couldn't have overtightened
you couldn't have overtightened
he couldn't have overtightened
we couldn't have overtightened
you couldn't have overtightened
they couldn't have overtightened	I couldn't have been overtightening
you couldn't have been overtightening
he couldn't have been overtightening
we couldn't have been overtightening
you couldn't have been overtightening
they couldn't have been overtightening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I overtighten?
could you overtighten?
could he overtighten?
could we overtighten?
could you overtighten?
could they overtighten? 	could I be overtightening?
could you be overtightening?
could he be overtightening?
could we be overtightening?
could you be overtightening?
could they be overtightening? 	could I have overtightened?
could you have overtightened?
could he have overtightened?
could we have overtightened?
could you have overtightened?
could they have overtightened? 	could I have been overtightening?
could you have been overtightening?
could he have been overtightening?
could we have been overtightening?
could you have been overtightening?
could they have been overtightening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I overtighten?
couldn't you overtighten?
couldn't he overtighten?
couldn't we overtighten?
couldn't you overtighten?
couldn't they overtighten? 	couldn't I be overtightening?
couldn't you be overtightening?
couldn't he be overtightening?
couldn't we be overtightening?
couldn't you be overtightening?
couldn't they be overtightening? 	couldn't I have overtightened?
couldn't you have overtightened?
couldn't he have overtightened?
couldn't we have overtightened?
couldn't you have overtightened?
couldn't they have overtightened? 	couldn't I have been overtightening?
couldn't you have been overtightening?
couldn't he have been overtightening?
couldn't we have been overtightening?
couldn't you have been overtightening?
couldn't they have been overtightening?