I can stammer you can stammer she can stammer we can stammer you can stammer they can stammer
V-ing form
I can be stammering you can be stammering she can be stammering we can be stammering you can be stammering they can be stammering
Perfect
I can have stammered you can have stammered she can have stammered we can have stammered you can have stammered they can have stammered
V-ing perfect
I can have been stammering you can have been stammering she can have been stammering we can have been stammering you can have been stammering they can have been stammering
Negation
Simple form
I cannot stammer you cannot stammer she cannot stammer we cannot stammer you cannot stammer they cannot stammer
V-ing form
I cannot be stammering you cannot be stammering she cannot be stammering we cannot be stammering you cannot be stammering they cannot be stammering
Perfect
I cannot have stammered you cannot have stammered she cannot have stammered we cannot have stammered you cannot have stammered they cannot have stammered
V-ing perfect
I cannot have been stammering you cannot have been stammering she cannot have been stammering we cannot have been stammering you cannot have been stammering they cannot have been stammering
Interrogative form
Simple form
can I stammer? can you stammer? can she stammer? can we stammer? can you stammer? can they stammer?
V-ing form
can I be stammering? can you be stammering? can she be stammering? can we be stammering? can you be stammering? can they be stammering?
Perfect
can I have stammered? can you have stammered? can she have stammered? can we have stammered? can you have stammered? can they have stammered?
V-ing perfect
can I have been stammering? can you have been stammering? can she have been stammering? can we have been stammering? can you have been stammering? can they have been stammering?
Interro-negative form
Simple form
can I not stammer? can you not stammer? can she not stammer? can we not stammer? can you not stammer? can they not stammer?
V-ing form
can I not be stammering? can you not be stammering? can she not be stammering? can we not be stammering? can you not be stammering? can they not be stammering?
Perfect
can I not have stammered? can you not have stammered? can she not have stammered? can we not have stammered? can you not have stammered? can they not have stammered?
V-ing perfect
can I not have been stammering? can you not have been stammering? can she not have been stammering? can we not have been stammering? can you not have been stammering? can they not have been stammering?