English verb conjugation
COULD DUN

Regular verb: dun - dunned - dunned

Affirmation

Simple form	V-ing form
I could dun you could dun he could dun we could dun you could dun they could dun	I could be dunning you could be dunning he could be dunning we could be dunning you could be dunning they could be dunning
Perfect	V-ing perfect
I could have dunned you could have dunned he could have dunned we could have dunned you could have dunned they could have dunned	I could have been dunning you could have been dunning he could have been dunning we could have been dunning you could have been dunning they could have been dunning

Negation

Simple form	V-ing form
I could not dun you could not dun he could not dun we could not dun you could not dun they could not dun	I could not be dunning you could not be dunning he could not be dunning we could not be dunning you could not be dunning they could not be dunning
Perfect	V-ing perfect
I could not have dunned you could not have dunned he could not have dunned we could not have dunned you could not have dunned they could not have dunned	I could not have been dunning you could not have been dunning he could not have been dunning we could not have been dunning you could not have been dunning they could not have been dunning

Interrogative form

Simple form	V-ing form
could I dun? could you dun? could he dun? could we dun? could you dun? could they dun?	could I be dunning? could you be dunning? could he be dunning? could we be dunning? could you be dunning? could they be dunning?
Perfect	V-ing perfect
could I have dunned? could you have dunned? could he have dunned? could we have dunned? could you have dunned? could they have dunned?	could I have been dunning? could you have been dunning? could he have been dunning? could we have been dunning? could you have been dunning? could they have been dunning?

Interro-negative form

Simple form	V-ing form
could I not dun? could you not dun? could he not dun? could we not dun? could you not dun? could they not dun?	could I not be dunning? could you not be dunning? could he not be dunning? could we not be dunning? could you not be dunning? could they not be dunning?
Perfect	V-ing perfect
could I not have dunned? could you not have dunned? could he not have dunned? could we not have dunned? could you not have dunned? could they not have dunned?	could I not have been dunning? could you not have been dunning? could he not have been dunning? could we not have been dunning? could you not have been dunning? could they not have been dunning?