must stammer
Regular verb: stammer - stammered- stammered

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

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

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

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