I could gangrene you could gangrene she could gangrene we could gangrene you could gangrene they could gangrene
V-ing form
I could be gangrening you could be gangrening she could be gangrening we could be gangrening you could be gangrening they could be gangrening
Perfect
I could have gangrened you could have gangrened she could have gangrened we could have gangrened you could have gangrened they could have gangrened
V-ing perfect
I could have been gangrening you could have been gangrening she could have been gangrening we could have been gangrening you could have been gangrening they could have been gangrening
Negation
Simple form
I could not gangrene you could not gangrene she could not gangrene we could not gangrene you could not gangrene they could not gangrene
V-ing form
I could not be gangrening you could not be gangrening she could not be gangrening we could not be gangrening you could not be gangrening they could not be gangrening
Perfect
I could not have gangrened you could not have gangrened she could not have gangrened we could not have gangrened you could not have gangrened they could not have gangrened
V-ing perfect
I could not have been gangrening you could not have been gangrening she could not have been gangrening we could not have been gangrening you could not have been gangrening they could not have been gangrening
Interrogative form
Simple form
could I gangrene? could you gangrene? could she gangrene? could we gangrene? could you gangrene? could they gangrene?
V-ing form
could I be gangrening? could you be gangrening? could she be gangrening? could we be gangrening? could you be gangrening? could they be gangrening?
Perfect
could I have gangrened? could you have gangrened? could she have gangrened? could we have gangrened? could you have gangrened? could they have gangrened?
V-ing perfect
could I have been gangrening? could you have been gangrening? could she have been gangrening? could we have been gangrening? could you have been gangrening? could they have been gangrening?
Interro-negative form
Simple form
could I not gangrene? could you not gangrene? could she not gangrene? could we not gangrene? could you not gangrene? could they not gangrene?
V-ing form
could I not be gangrening? could you not be gangrening? could she not be gangrening? could we not be gangrening? could you not be gangrening? could they not be gangrening?
Perfect
could I not have gangrened? could you not have gangrened? could she not have gangrened? could we not have gangrened? could you not have gangrened? could they not have gangrened?
V-ing perfect
could I not have been gangrening? could you not have been gangrening? could she not have been gangrening? could we not have been gangrening? could you not have been gangrening? could they not have been gangrening?