English verb conjugation
COULD RUFF

Regular verb: ruff - ruffed - ruffed

Affirmation

Simple form	V-ing form
I could ruff you could ruff she could ruff we could ruff you could ruff they could ruff	I could be ruffing you could be ruffing she could be ruffing we could be ruffing you could be ruffing they could be ruffing
Perfect	V-ing perfect
I could have ruffed you could have ruffed she could have ruffed we could have ruffed you could have ruffed they could have ruffed	I could have been ruffing you could have been ruffing she could have been ruffing we could have been ruffing you could have been ruffing they could have been ruffing

Negation

Simple form	V-ing form
I could not ruff you could not ruff she could not ruff we could not ruff you could not ruff they could not ruff	I could not be ruffing you could not be ruffing she could not be ruffing we could not be ruffing you could not be ruffing they could not be ruffing
Perfect	V-ing perfect
I could not have ruffed you could not have ruffed she could not have ruffed we could not have ruffed you could not have ruffed they could not have ruffed	I could not have been ruffing you could not have been ruffing she could not have been ruffing we could not have been ruffing you could not have been ruffing they could not have been ruffing

Interrogative form

Simple form	V-ing form
could I ruff? could you ruff? could she ruff? could we ruff? could you ruff? could they ruff?	could I be ruffing? could you be ruffing? could she be ruffing? could we be ruffing? could you be ruffing? could they be ruffing?
Perfect	V-ing perfect
could I have ruffed? could you have ruffed? could she have ruffed? could we have ruffed? could you have ruffed? could they have ruffed?	could I have been ruffing? could you have been ruffing? could she have been ruffing? could we have been ruffing? could you have been ruffing? could they have been ruffing?

Interro-negative form

Simple form	V-ing form
could I not ruff? could you not ruff? could she not ruff? could we not ruff? could you not ruff? could they not ruff?	could I not be ruffing? could you not be ruffing? could she not be ruffing? could we not be ruffing? could you not be ruffing? could they not be ruffing?
Perfect	V-ing perfect
could I not have ruffed? could you not have ruffed? could she not have ruffed? could we not have ruffed? could you not have ruffed? could they not have ruffed?	could I not have been ruffing? could you not have been ruffing? could she not have been ruffing? could we not have been ruffing? could you not have been ruffing? could they not have been ruffing?