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