I could omen you could omen he could omen we could omen you could omen they could omen
V-ing form
I could be omening you could be omening he could be omening we could be omening you could be omening they could be omening
Perfect
I could have omened you could have omened he could have omened we could have omened you could have omened they could have omened
V-ing perfect
I could have been omening you could have been omening he could have been omening we could have been omening you could have been omening they could have been omening
Negation
Simple form
I could not omen you could not omen he could not omen we could not omen you could not omen they could not omen
V-ing form
I could not be omening you could not be omening he could not be omening we could not be omening you could not be omening they could not be omening
Perfect
I could not have omened you could not have omened he could not have omened we could not have omened you could not have omened they could not have omened
V-ing perfect
I could not have been omening you could not have been omening he could not have been omening we could not have been omening you could not have been omening they could not have been omening
Interrogative form
Simple form
could I omen? could you omen? could he omen? could we omen? could you omen? could they omen?
V-ing form
could I be omening? could you be omening? could he be omening? could we be omening? could you be omening? could they be omening?
Perfect
could I have omened? could you have omened? could he have omened? could we have omened? could you have omened? could they have omened?
V-ing perfect
could I have been omening? could you have been omening? could he have been omening? could we have been omening? could you have been omening? could they have been omening?
Interro-negative form
Simple form
could I not omen? could you not omen? could he not omen? could we not omen? could you not omen? could they not omen?
V-ing form
could I not be omening? could you not be omening? could he not be omening? could we not be omening? could you not be omening? could they not be omening?
Perfect
could I not have omened? could you not have omened? could he not have omened? could we not have omened? could you not have omened? could they not have omened?
V-ing perfect
could I not have been omening? could you not have been omening? could he not have been omening? could we not have been omening? could you not have been omening? could they not have been omening?