English verb conjugation
CAN ADD

Regular verb: add - added - added

Affirmation

Simple form	V-ing form
I can add you can add he can add we can add you can add they can add	I can be adding you can be adding he can be adding we can be adding you can be adding they can be adding
Perfect	V-ing perfect
I can have added you can have added he can have added we can have added you can have added they can have added	I can have been adding you can have been adding he can have been adding we can have been adding you can have been adding they can have been adding

Negation

Simple form	V-ing form
I can't add you can't add he can't add we can't add you can't add they can't add	I can't be adding you can't be adding he can't be adding we can't be adding you can't be adding they can't be adding
Perfect	V-ing perfect
I can't have added you can't have added he can't have added we can't have added you can't have added they can't have added	I can't have been adding you can't have been adding he can't have been adding we can't have been adding you can't have been adding they can't have been adding

Interrogative form

Simple form	V-ing form
can I add? can you add? can he add? can we add? can you add? can they add?	can I be adding? can you be adding? can he be adding? can we be adding? can you be adding? can they be adding?
Perfect	V-ing perfect
can I have added? can you have added? can he have added? can we have added? can you have added? can they have added?	can I have been adding? can you have been adding? can he have been adding? can we have been adding? can you have been adding? can they have been adding?

Interro-negative form

Simple form	V-ing form
can't I add? can't you add? can't he add? can't we add? can't you add? can't they add?	can't I be adding? can't you be adding? can't he be adding? can't we be adding? can't you be adding? can't they be adding?
Perfect	V-ing perfect
can't I have added? can't you have added? can't he have added? can't we have added? can't you have added? can't they have added?	can't I have been adding? can't you have been adding? can't he have been adding? can't we have been adding? can't you have been adding? can't they have been adding?