could stammer
Regular verb: stammer - stammered- stammered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could stammer
you could stammer
he could stammer
we could stammer
you could stammer
they could stammer 	I could be stammering
you could be stammering
he could be stammering
we could be stammering
you could be stammering
they could be stammering	I could have stammered
you could have stammered
he could have stammered
we could have stammered
you could have stammered
they could have stammered	I could have been stammering
you could have been stammering
he could have been stammering
we could have been stammering
you could have been stammering
they could have been stammering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't stammer
you couldn't stammer
he couldn't stammer
we couldn't stammer
you couldn't stammer
they couldn't stammer 	I couldn't be stammering
you couldn't be stammering
he couldn't be stammering
we couldn't be stammering
you couldn't be stammering
they couldn't be stammering	I couldn't have stammered
you couldn't have stammered
he couldn't have stammered
we couldn't have stammered
you couldn't have stammered
they couldn't have stammered	I couldn't have been stammering
you couldn't have been stammering
he couldn't have been stammering
we couldn't have been stammering
you couldn't have been stammering
they couldn't have been stammering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I stammer?
could you stammer?
could he stammer?
could we stammer?
could you stammer?
could they stammer? 	could I be stammering?
could you be stammering?
could he be stammering?
could we be stammering?
could you be stammering?
could they be stammering? 	could I have stammered?
could you have stammered?
could he have stammered?
could we have stammered?
could you have stammered?
could they have stammered? 	could I have been stammering?
could you have been stammering?
could he have been stammering?
could we have been stammering?
could you have been stammering?
could they have been stammering? 	

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