I must stammer you must stammer she must stammer we must stammer you must stammer they must stammer
V-ing form
I must be stammering you must be stammering she must be stammering we must be stammering you must be stammering they must be stammering
Perfect
I must have stammered you must have stammered she must have stammered we must have stammered you must have stammered they must have stammered
V-ing perfect
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
I must not stammer you must not stammer she must not stammer we must not stammer you must not stammer they must not stammer
V-ing form
I must not be stammering you must not be stammering she must not be stammering we must not be stammering you must not be stammering they must not be stammering
Perfect
I must not have stammered you must not have stammered she must not have stammered we must not have stammered you must not have stammered they must not have stammered
V-ing perfect
I must not have been stammering you must not have been stammering she must not have been stammering we must not have been stammering you must not have been stammering they must not have been stammering
Interrogative form
Simple form
must I stammer? must you stammer? must she stammer? must we stammer? must you stammer? must they stammer?
V-ing form
must I be stammering? must you be stammering? must she be stammering? must we be stammering? must you be stammering? must they be stammering?
Perfect
must I have stammered? must you have stammered? must she have stammered? must we have stammered? must you have stammered? must they have stammered?
V-ing perfect
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
must I not stammer? must you not stammer? must she not stammer? must we not stammer? must you not stammer? must they not stammer?
V-ing form
must I not be stammering? must you not be stammering? must she not be stammering? must we not be stammering? must you not be stammering? must they not be stammering?
Perfect
must I not have stammered? must you not have stammered? must she not have stammered? must we not have stammered? must you not have stammered? must they not have stammered?
V-ing perfect
must I not have been stammering? must you not have been stammering? must she not have been stammering? must we not have been stammering? must you not have been stammering? must they not have been stammering?