could prefix
Regular verb: prefix - prefixed- prefixed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could prefix
you could prefix
she could prefix
we could prefix
you could prefix
they could prefix 	I could be prefixing
you could be prefixing
she could be prefixing
we could be prefixing
you could be prefixing
they could be prefixing	I could have prefixed
you could have prefixed
she could have prefixed
we could have prefixed
you could have prefixed
they could have prefixed	I could have been prefixing
you could have been prefixing
she could have been prefixing
we could have been prefixing
you could have been prefixing
they could have been prefixing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not prefix
you could not prefix
she could not prefix
we could not prefix
you could not prefix
they could not prefix 	I could not be prefixing
you could not be prefixing
she could not be prefixing
we could not be prefixing
you could not be prefixing
they could not be prefixing	I could not have prefixed
you could not have prefixed
she could not have prefixed
we could not have prefixed
you could not have prefixed
they could not have prefixed	I could not have been prefixing
you could not have been prefixing
she could not have been prefixing
we could not have been prefixing
you could not have been prefixing
they could not have been prefixing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I prefix?
could you prefix?
could she prefix?
could we prefix?
could you prefix?
could they prefix? 	could I be prefixing?
could you be prefixing?
could she be prefixing?
could we be prefixing?
could you be prefixing?
could they be prefixing? 	could I have prefixed?
could you have prefixed?
could she have prefixed?
could we have prefixed?
could you have prefixed?
could they have prefixed? 	could I have been prefixing?
could you have been prefixing?
could she have been prefixing?
could we have been prefixing?
could you have been prefixing?
could they have been prefixing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not prefix?
could you not prefix?
could she not prefix?
could we not prefix?
could you not prefix?
could they not prefix? 	could I not be prefixing?
could you not be prefixing?
could she not be prefixing?
could we not be prefixing?
could you not be prefixing?
could they not be prefixing? 	could I not have prefixed?
could you not have prefixed?
could she not have prefixed?
could we not have prefixed?
could you not have prefixed?
could they not have prefixed? 	could I not have been prefixing?
could you not have been prefixing?
could she not have been prefixing?
could we not have been prefixing?
could you not have been prefixing?
could they not have been prefixing?