could hyphen
Regular verb: hyphen - hyphened- hyphened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could hyphen
you could hyphen
he could hyphen
we could hyphen
you could hyphen
they could hyphen 	I could be hyphening
you could be hyphening
he could be hyphening
we could be hyphening
you could be hyphening
they could be hyphening	I could have hyphened
you could have hyphened
he could have hyphened
we could have hyphened
you could have hyphened
they could have hyphened	I could have been hyphening
you could have been hyphening
he could have been hyphening
we could have been hyphening
you could have been hyphening
they could have been hyphening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not hyphen
you could not hyphen
he could not hyphen
we could not hyphen
you could not hyphen
they could not hyphen 	I could not be hyphening
you could not be hyphening
he could not be hyphening
we could not be hyphening
you could not be hyphening
they could not be hyphening	I could not have hyphened
you could not have hyphened
he could not have hyphened
we could not have hyphened
you could not have hyphened
they could not have hyphened	I could not have been hyphening
you could not have been hyphening
he could not have been hyphening
we could not have been hyphening
you could not have been hyphening
they could not have been hyphening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I hyphen?
could you hyphen?
could he hyphen?
could we hyphen?
could you hyphen?
could they hyphen? 	could I be hyphening?
could you be hyphening?
could he be hyphening?
could we be hyphening?
could you be hyphening?
could they be hyphening? 	could I have hyphened?
could you have hyphened?
could he have hyphened?
could we have hyphened?
could you have hyphened?
could they have hyphened? 	could I have been hyphening?
could you have been hyphening?
could he have been hyphening?
could we have been hyphening?
could you have been hyphening?
could they have been hyphening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not hyphen?
could you not hyphen?
could he not hyphen?
could we not hyphen?
could you not hyphen?
could they not hyphen? 	could I not be hyphening?
could you not be hyphening?
could he not be hyphening?
could we not be hyphening?
could you not be hyphening?
could they not be hyphening? 	could I not have hyphened?
could you not have hyphened?
could he not have hyphened?
could we not have hyphened?
could you not have hyphened?
could they not have hyphened? 	could I not have been hyphening?
could you not have been hyphening?
could he not have been hyphening?
could we not have been hyphening?
could you not have been hyphening?
could they not have been hyphening?