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 couldn't ruff you couldn't ruff she couldn't ruff we couldn't ruff you couldn't ruff they couldn't ruff	I couldn't be ruffing you couldn't be ruffing she couldn't be ruffing we couldn't be ruffing you couldn't be ruffing they couldn't be ruffing
Perfect	V-ing perfect
I couldn't have ruffed you couldn't have ruffed she couldn't have ruffed we couldn't have ruffed you couldn't have ruffed they couldn't have ruffed	I couldn't have been ruffing you couldn't have been ruffing she couldn't have been ruffing we couldn't have been ruffing you couldn't have been ruffing they couldn't 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
couldn't I ruff? couldn't you ruff? couldn't she ruff? couldn't we ruff? couldn't you ruff? couldn't they ruff?	couldn't I be ruffing? couldn't you be ruffing? couldn't she be ruffing? couldn't we be ruffing? couldn't you be ruffing? couldn't they be ruffing?
Perfect	V-ing perfect
couldn't I have ruffed? couldn't you have ruffed? couldn't she have ruffed? couldn't we have ruffed? couldn't you have ruffed? couldn't they have ruffed?	couldn't I have been ruffing? couldn't you have been ruffing? couldn't she have been ruffing? couldn't we have been ruffing? couldn't you have been ruffing? couldn't they have been ruffing?