could attach
Regular verb: attach - attached- attached

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could attach
you could attach
she could attach
we could attach
you could attach
they could attach 	I could be attaching
you could be attaching
she could be attaching
we could be attaching
you could be attaching
they could be attaching	I could have attached
you could have attached
she could have attached
we could have attached
you could have attached
they could have attached	I could have been attaching
you could have been attaching
she could have been attaching
we could have been attaching
you could have been attaching
they could have been attaching	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't attach
you couldn't attach
she couldn't attach
we couldn't attach
you couldn't attach
they couldn't attach 	I couldn't be attaching
you couldn't be attaching
she couldn't be attaching
we couldn't be attaching
you couldn't be attaching
they couldn't be attaching	I couldn't have attached
you couldn't have attached
she couldn't have attached
we couldn't have attached
you couldn't have attached
they couldn't have attached	I couldn't have been attaching
you couldn't have been attaching
she couldn't have been attaching
we couldn't have been attaching
you couldn't have been attaching
they couldn't have been attaching	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I attach?
could you attach?
could she attach?
could we attach?
could you attach?
could they attach? 	could I be attaching?
could you be attaching?
could she be attaching?
could we be attaching?
could you be attaching?
could they be attaching? 	could I have attached?
could you have attached?
could she have attached?
could we have attached?
could you have attached?
could they have attached? 	could I have been attaching?
could you have been attaching?
could she have been attaching?
could we have been attaching?
could you have been attaching?
could they have been attaching? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I attach?
couldn't you attach?
couldn't she attach?
couldn't we attach?
couldn't you attach?
couldn't they attach? 	couldn't I be attaching?
couldn't you be attaching?
couldn't she be attaching?
couldn't we be attaching?
couldn't you be attaching?
couldn't they be attaching? 	couldn't I have attached?
couldn't you have attached?
couldn't she have attached?
couldn't we have attached?
couldn't you have attached?
couldn't they have attached? 	couldn't I have been attaching?
couldn't you have been attaching?
couldn't she have been attaching?
couldn't we have been attaching?
couldn't you have been attaching?
couldn't they have been attaching?