English verb conjugation
COULD RIB

Regular verb: rib - ribed - ribed

Affirmation

Simple form	V-ing form
I could rib you could rib she could rib we could rib you could rib they could rib	I could be ribing you could be ribing she could be ribing we could be ribing you could be ribing they could be ribing
Perfect	V-ing perfect
I could have ribed you could have ribed she could have ribed we could have ribed you could have ribed they could have ribed	I could have been ribing you could have been ribing she could have been ribing we could have been ribing you could have been ribing they could have been ribing

Negation

Simple form	V-ing form
I could not rib you could not rib she could not rib we could not rib you could not rib they could not rib	I could not be ribing you could not be ribing she could not be ribing we could not be ribing you could not be ribing they could not be ribing
Perfect	V-ing perfect
I could not have ribed you could not have ribed she could not have ribed we could not have ribed you could not have ribed they could not have ribed	I could not have been ribing you could not have been ribing she could not have been ribing we could not have been ribing you could not have been ribing they could not have been ribing

Interrogative form

Simple form	V-ing form
could I rib? could you rib? could she rib? could we rib? could you rib? could they rib?	could I be ribing? could you be ribing? could she be ribing? could we be ribing? could you be ribing? could they be ribing?
Perfect	V-ing perfect
could I have ribed? could you have ribed? could she have ribed? could we have ribed? could you have ribed? could they have ribed?	could I have been ribing? could you have been ribing? could she have been ribing? could we have been ribing? could you have been ribing? could they have been ribing?

Interro-negative form

Simple form	V-ing form
could I not rib? could you not rib? could she not rib? could we not rib? could you not rib? could they not rib?	could I not be ribing? could you not be ribing? could she not be ribing? could we not be ribing? could you not be ribing? could they not be ribing?
Perfect	V-ing perfect
could I not have ribed? could you not have ribed? could she not have ribed? could we not have ribed? could you not have ribed? could they not have ribed?	could I not have been ribing? could you not have been ribing? could she not have been ribing? could we not have been ribing? could you not have been ribing? could they not have been ribing?