must shutter
Regular verb: shutter - shuttered- shuttered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must shutter
you must shutter
she must shutter
we must shutter
you must shutter
they must shutter 	I must be shuttering
you must be shuttering
she must be shuttering
we must be shuttering
you must be shuttering
they must be shuttering	I must have shuttered
you must have shuttered
she must have shuttered
we must have shuttered
you must have shuttered
they must have shuttered	I must have been shuttering
you must have been shuttering
she must have been shuttering
we must have been shuttering
you must have been shuttering
they must have been shuttering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't shutter
you mustn't shutter
she mustn't shutter
we mustn't shutter
you mustn't shutter
they mustn't shutter 	I mustn't be shuttering
you mustn't be shuttering
she mustn't be shuttering
we mustn't be shuttering
you mustn't be shuttering
they mustn't be shuttering	I mustn't have shuttered
you mustn't have shuttered
she mustn't have shuttered
we mustn't have shuttered
you mustn't have shuttered
they mustn't have shuttered	I mustn't have been shuttering
you mustn't have been shuttering
she mustn't have been shuttering
we mustn't have been shuttering
you mustn't have been shuttering
they mustn't have been shuttering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I shutter?
must you shutter?
must she shutter?
must we shutter?
must you shutter?
must they shutter? 	must I be shuttering?
must you be shuttering?
must she be shuttering?
must we be shuttering?
must you be shuttering?
must they be shuttering? 	must I have shuttered?
must you have shuttered?
must she have shuttered?
must we have shuttered?
must you have shuttered?
must they have shuttered? 	must I have been shuttering?
must you have been shuttering?
must she have been shuttering?
must we have been shuttering?
must you have been shuttering?
must they have been shuttering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I shutter?
mustn't you shutter?
mustn't she shutter?
mustn't we shutter?
mustn't you shutter?
mustn't they shutter? 	mustn't I be shuttering?
mustn't you be shuttering?
mustn't she be shuttering?
mustn't we be shuttering?
mustn't you be shuttering?
mustn't they be shuttering? 	mustn't I have shuttered?
mustn't you have shuttered?
mustn't she have shuttered?
mustn't we have shuttered?
mustn't you have shuttered?
mustn't they have shuttered? 	mustn't I have been shuttering?
mustn't you have been shuttering?
mustn't she have been shuttering?
mustn't we have been shuttering?
mustn't you have been shuttering?
mustn't they have been shuttering?