must downshift
Regular verb: downshift - downshifted- downshifted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must downshift
you must downshift
he must downshift
we must downshift
you must downshift
they must downshift 	I must be downshifting
you must be downshifting
he must be downshifting
we must be downshifting
you must be downshifting
they must be downshifting	I must have downshifted
you must have downshifted
he must have downshifted
we must have downshifted
you must have downshifted
they must have downshifted	I must have been downshifting
you must have been downshifting
he must have been downshifting
we must have been downshifting
you must have been downshifting
they must have been downshifting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't downshift
you mustn't downshift
he mustn't downshift
we mustn't downshift
you mustn't downshift
they mustn't downshift 	I mustn't be downshifting
you mustn't be downshifting
he mustn't be downshifting
we mustn't be downshifting
you mustn't be downshifting
they mustn't be downshifting	I mustn't have downshifted
you mustn't have downshifted
he mustn't have downshifted
we mustn't have downshifted
you mustn't have downshifted
they mustn't have downshifted	I mustn't have been downshifting
you mustn't have been downshifting
he mustn't have been downshifting
we mustn't have been downshifting
you mustn't have been downshifting
they mustn't have been downshifting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I downshift?
must you downshift?
must he downshift?
must we downshift?
must you downshift?
must they downshift? 	must I be downshifting?
must you be downshifting?
must he be downshifting?
must we be downshifting?
must you be downshifting?
must they be downshifting? 	must I have downshifted?
must you have downshifted?
must he have downshifted?
must we have downshifted?
must you have downshifted?
must they have downshifted? 	must I have been downshifting?
must you have been downshifting?
must he have been downshifting?
must we have been downshifting?
must you have been downshifting?
must they have been downshifting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I downshift?
mustn't you downshift?
mustn't he downshift?
mustn't we downshift?
mustn't you downshift?
mustn't they downshift? 	mustn't I be downshifting?
mustn't you be downshifting?
mustn't he be downshifting?
mustn't we be downshifting?
mustn't you be downshifting?
mustn't they be downshifting? 	mustn't I have downshifted?
mustn't you have downshifted?
mustn't he have downshifted?
mustn't we have downshifted?
mustn't you have downshifted?
mustn't they have downshifted? 	mustn't I have been downshifting?
mustn't you have been downshifting?
mustn't he have been downshifting?
mustn't we have been downshifting?
mustn't you have been downshifting?
mustn't they have been downshifting?