could suffix
Regular verb: suffix - suffixed- suffixed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could suffix
you could suffix
she could suffix
we could suffix
you could suffix
they could suffix 	I could be suffixing
you could be suffixing
she could be suffixing
we could be suffixing
you could be suffixing
they could be suffixing	I could have suffixed
you could have suffixed
she 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
she 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 couldn't suffix
you couldn't suffix
she couldn't suffix
we couldn't suffix
you couldn't suffix
they couldn't suffix 	I couldn't be suffixing
you couldn't be suffixing
she couldn't be suffixing
we couldn't be suffixing
you couldn't be suffixing
they couldn't be suffixing	I couldn't have suffixed
you couldn't have suffixed
she couldn't have suffixed
we couldn't have suffixed
you couldn't have suffixed
they couldn't have suffixed	I couldn't have been suffixing
you couldn't have been suffixing
she couldn't have been suffixing
we couldn't have been suffixing
you couldn't have been suffixing
they couldn't have been suffixing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I suffix?
could you suffix?
could she suffix?
could we suffix?
could you suffix?
could they suffix? 	could I be suffixing?
could you be suffixing?
could she be suffixing?
could we be suffixing?
could you be suffixing?
could they be suffixing? 	could I have suffixed?
could you have suffixed?
could she 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 she 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 	
couldn't I suffix?
couldn't you suffix?
couldn't she suffix?
couldn't we suffix?
couldn't you suffix?
couldn't they suffix? 	couldn't I be suffixing?
couldn't you be suffixing?
couldn't she be suffixing?
couldn't we be suffixing?
couldn't you be suffixing?
couldn't they be suffixing? 	couldn't I have suffixed?
couldn't you have suffixed?
couldn't she have suffixed?
couldn't we have suffixed?
couldn't you have suffixed?
couldn't they have suffixed? 	couldn't I have been suffixing?
couldn't you have been suffixing?
couldn't she have been suffixing?
couldn't we have been suffixing?
couldn't you have been suffixing?
couldn't they have been suffixing?