could add
Regular verb: add - added- added

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could add
you could add
she could add
we could add
you could add
they could add 	I could be adding
you could be adding
she could be adding
we could be adding
you could be adding
they could be adding	I could have added
you could have added
she could have added
we could have added
you could have added
they could have added	I could have been adding
you could have been adding
she could have been adding
we could have been adding
you could have been adding
they could have been adding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't add
you couldn't add
she couldn't add
we couldn't add
you couldn't add
they couldn't add 	I couldn't be adding
you couldn't be adding
she couldn't be adding
we couldn't be adding
you couldn't be adding
they couldn't be adding	I couldn't have added
you couldn't have added
she couldn't have added
we couldn't have added
you couldn't have added
they couldn't have added	I couldn't have been adding
you couldn't have been adding
she couldn't have been adding
we couldn't have been adding
you couldn't have been adding
they couldn't have been adding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I add?
could you add?
could she add?
could we add?
could you add?
could they add? 	could I be adding?
could you be adding?
could she be adding?
could we be adding?
could you be adding?
could they be adding? 	could I have added?
could you have added?
could she have added?
could we have added?
could you have added?
could they have added? 	could I have been adding?
could you have been adding?
could she have been adding?
could we have been adding?
could you have been adding?
could they have been adding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I add?
couldn't you add?
couldn't she add?
couldn't we add?
couldn't you add?
couldn't they add? 	couldn't I be adding?
couldn't you be adding?
couldn't she be adding?
couldn't we be adding?
couldn't you be adding?
couldn't they be adding? 	couldn't I have added?
couldn't you have added?
couldn't she have added?
couldn't we have added?
couldn't you have added?
couldn't they have added? 	couldn't I have been adding?
couldn't you have been adding?
couldn't she have been adding?
couldn't we have been adding?
couldn't you have been adding?
couldn't they have been adding?