I can stammer you can stammer he can stammer we can stammer you can stammer they can stammer
V-ing form
I can be stammering you can be stammering he can be stammering we can be stammering you can be stammering they can be stammering
Perfect
I can have stammered you can have stammered he 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 he can have been stammering we can have been stammering you can have been stammering they can have been stammering
Negation
Simple form
I can't stammer you can't stammer he can't stammer we can't stammer you can't stammer they can't stammer
V-ing form
I can't be stammering you can't be stammering he can't be stammering we can't be stammering you can't be stammering they can't be stammering
Perfect
I can't have stammered you can't have stammered he can't have stammered we can't have stammered you can't have stammered they can't have stammered
V-ing perfect
I can't have been stammering you can't have been stammering he can't have been stammering we can't have been stammering you can't have been stammering they can't have been stammering
Interrogative form
Simple form
can I stammer? can you stammer? can he stammer? can we stammer? can you stammer? can they stammer?
V-ing form
can I be stammering? can you be stammering? can he be stammering? can we be stammering? can you be stammering? can they be stammering?
Perfect
can I have stammered? can you have stammered? can he 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 he have been stammering? can we have been stammering? can you have been stammering? can they have been stammering?
Interro-negative form
Simple form
can't I stammer? can't you stammer? can't he stammer? can't we stammer? can't you stammer? can't they stammer?
V-ing form
can't I be stammering? can't you be stammering? can't he be stammering? can't we be stammering? can't you be stammering? can't they be stammering?
Perfect
can't I have stammered? can't you have stammered? can't he have stammered? can't we have stammered? can't you have stammered? can't they have stammered?
V-ing perfect
can't I have been stammering? can't you have been stammering? can't he have been stammering? can't we have been stammering? can't you have been stammering? can't they have been stammering?