I could gangrene you could gangrene he could gangrene we could gangrene you could gangrene they could gangrene
V-ing form
I could be gangrening you could be gangrening he could be gangrening we could be gangrening you could be gangrening they could be gangrening
Perfect
I could have gangrened you could have gangrened he 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 he could have been gangrening we could have been gangrening you could have been gangrening they could have been gangrening
Negation
Simple form
I couldn't gangrene you couldn't gangrene he couldn't gangrene we couldn't gangrene you couldn't gangrene they couldn't gangrene
V-ing form
I couldn't be gangrening you couldn't be gangrening he couldn't be gangrening we couldn't be gangrening you couldn't be gangrening they couldn't be gangrening
Perfect
I couldn't have gangrened you couldn't have gangrened he couldn't have gangrened we couldn't have gangrened you couldn't have gangrened they couldn't have gangrened
V-ing perfect
I couldn't have been gangrening you couldn't have been gangrening he couldn't have been gangrening we couldn't have been gangrening you couldn't have been gangrening they couldn't have been gangrening
Interrogative form
Simple form
could I gangrene? could you gangrene? could he gangrene? could we gangrene? could you gangrene? could they gangrene?
V-ing form
could I be gangrening? could you be gangrening? could he be gangrening? could we be gangrening? could you be gangrening? could they be gangrening?
Perfect
could I have gangrened? could you have gangrened? could he 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 he have been gangrening? could we have been gangrening? could you have been gangrening? could they have been gangrening?
Interro-negative form
Simple form
couldn't I gangrene? couldn't you gangrene? couldn't he gangrene? couldn't we gangrene? couldn't you gangrene? couldn't they gangrene?
V-ing form
couldn't I be gangrening? couldn't you be gangrening? couldn't he be gangrening? couldn't we be gangrening? couldn't you be gangrening? couldn't they be gangrening?
Perfect
couldn't I have gangrened? couldn't you have gangrened? couldn't he have gangrened? couldn't we have gangrened? couldn't you have gangrened? couldn't they have gangrened?
V-ing perfect
couldn't I have been gangrening? couldn't you have been gangrening? couldn't he have been gangrening? couldn't we have been gangrening? couldn't you have been gangrening? couldn't they have been gangrening?