I can leather you can leather he can leather we can leather you can leather they can leather
V-ing form
I can be leathering you can be leathering he can be leathering we can be leathering you can be leathering they can be leathering
Perfect
I can have leathered you can have leathered he can have leathered we can have leathered you can have leathered they can have leathered
V-ing perfect
I can have been leathering you can have been leathering he can have been leathering we can have been leathering you can have been leathering they can have been leathering
Negation
Simple form
I cannot leather you cannot leather he cannot leather we cannot leather you cannot leather they cannot leather
V-ing form
I cannot be leathering you cannot be leathering he cannot be leathering we cannot be leathering you cannot be leathering they cannot be leathering
Perfect
I cannot have leathered you cannot have leathered he cannot have leathered we cannot have leathered you cannot have leathered they cannot have leathered
V-ing perfect
I cannot have been leathering you cannot have been leathering he cannot have been leathering we cannot have been leathering you cannot have been leathering they cannot have been leathering
Interrogative form
Simple form
can I leather? can you leather? can he leather? can we leather? can you leather? can they leather?
V-ing form
can I be leathering? can you be leathering? can he be leathering? can we be leathering? can you be leathering? can they be leathering?
Perfect
can I have leathered? can you have leathered? can he have leathered? can we have leathered? can you have leathered? can they have leathered?
V-ing perfect
can I have been leathering? can you have been leathering? can he have been leathering? can we have been leathering? can you have been leathering? can they have been leathering?
Interro-negative form
Simple form
can I not leather? can you not leather? can he not leather? can we not leather? can you not leather? can they not leather?
V-ing form
can I not be leathering? can you not be leathering? can he not be leathering? can we not be leathering? can you not be leathering? can they not be leathering?
Perfect
can I not have leathered? can you not have leathered? can he not have leathered? can we not have leathered? can you not have leathered? can they not have leathered?
V-ing perfect
can I not have been leathering? can you not have been leathering? can he not have been leathering? can we not have been leathering? can you not have been leathering? can they not have been leathering?