must brighten
Regular verb: brighten - brightened- brightened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must brighten
you must brighten
she must brighten
we must brighten
you must brighten
they must brighten 	I must be brightening
you must be brightening
she must be brightening
we must be brightening
you must be brightening
they must be brightening	I must have brightened
you must have brightened
she must have brightened
we must have brightened
you must have brightened
they must have brightened	I must have been brightening
you must have been brightening
she must have been brightening
we must have been brightening
you must have been brightening
they must have been brightening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't brighten
you mustn't brighten
she mustn't brighten
we mustn't brighten
you mustn't brighten
they mustn't brighten 	I mustn't be brightening
you mustn't be brightening
she mustn't be brightening
we mustn't be brightening
you mustn't be brightening
they mustn't be brightening	I mustn't have brightened
you mustn't have brightened
she mustn't have brightened
we mustn't have brightened
you mustn't have brightened
they mustn't have brightened	I mustn't have been brightening
you mustn't have been brightening
she mustn't have been brightening
we mustn't have been brightening
you mustn't have been brightening
they mustn't have been brightening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I brighten?
must you brighten?
must she brighten?
must we brighten?
must you brighten?
must they brighten? 	must I be brightening?
must you be brightening?
must she be brightening?
must we be brightening?
must you be brightening?
must they be brightening? 	must I have brightened?
must you have brightened?
must she have brightened?
must we have brightened?
must you have brightened?
must they have brightened? 	must I have been brightening?
must you have been brightening?
must she have been brightening?
must we have been brightening?
must you have been brightening?
must they have been brightening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I brighten?
mustn't you brighten?
mustn't she brighten?
mustn't we brighten?
mustn't you brighten?
mustn't they brighten? 	mustn't I be brightening?
mustn't you be brightening?
mustn't she be brightening?
mustn't we be brightening?
mustn't you be brightening?
mustn't they be brightening? 	mustn't I have brightened?
mustn't you have brightened?
mustn't she have brightened?
mustn't we have brightened?
mustn't you have brightened?
mustn't they have brightened? 	mustn't I have been brightening?
mustn't you have been brightening?
mustn't she have been brightening?
mustn't we have been brightening?
mustn't you have been brightening?
mustn't they have been brightening?