could suffix
Regular verb: suffix - suffixed- suffixed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could suffix
you could suffix
he could suffix
we could suffix
you could suffix
they could suffix 	I could be suffixing
you could be suffixing
he could be suffixing
we could be suffixing
you could be suffixing
they could be suffixing	I could have suffixed
you could have suffixed
he could have suffixed
we could have suffixed
you could have suffixed
they could have suffixed	I could have been suffixing
you could have been suffixing
he could have been suffixing
we could have been suffixing
you could have been suffixing
they could have been suffixing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not suffix
you could not suffix
he could not suffix
we could not suffix
you could not suffix
they could not suffix 	I could not be suffixing
you could not be suffixing
he could not be suffixing
we could not be suffixing
you could not be suffixing
they could not be suffixing	I could not have suffixed
you could not have suffixed
he could not have suffixed
we could not have suffixed
you could not have suffixed
they could not have suffixed	I could not have been suffixing
you could not have been suffixing
he could not have been suffixing
we could not have been suffixing
you could not have been suffixing
they could not have been suffixing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I suffix?
could you suffix?
could he suffix?
could we suffix?
could you suffix?
could they suffix? 	could I be suffixing?
could you be suffixing?
could he be suffixing?
could we be suffixing?
could you be suffixing?
could they be suffixing? 	could I have suffixed?
could you have suffixed?
could he have suffixed?
could we have suffixed?
could you have suffixed?
could they have suffixed? 	could I have been suffixing?
could you have been suffixing?
could he have been suffixing?
could we have been suffixing?
could you have been suffixing?
could they have been suffixing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not suffix?
could you not suffix?
could he not suffix?
could we not suffix?
could you not suffix?
could they not suffix? 	could I not be suffixing?
could you not be suffixing?
could he not be suffixing?
could we not be suffixing?
could you not be suffixing?
could they not be suffixing? 	could I not have suffixed?
could you not have suffixed?
could he not have suffixed?
could we not have suffixed?
could you not have suffixed?
could they not have suffixed? 	could I not have been suffixing?
could you not have been suffixing?
could he not have been suffixing?
could we not have been suffixing?
could you not have been suffixing?
could they not have been suffixing?