must lessen
Verbo regular: lessen - lessened- lessened

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must lessen
you must lessen
she must lessen
we must lessen
you must lessen
they must lessen 	I must be lessening
you must be lessening
she must be lessening
we must be lessening
you must be lessening
they must be lessening	I must have lessened
you must have lessened
she must have lessened
we must have lessened
you must have lessened
they must have lessened	I must have been lessening
you must have been lessening
she must have been lessening
we must have been lessening
you must have been lessening
they must have been lessening	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I mustn't lessen
you mustn't lessen
she mustn't lessen
we mustn't lessen
you mustn't lessen
they mustn't lessen 	I mustn't be lessening
you mustn't be lessening
she mustn't be lessening
we mustn't be lessening
you mustn't be lessening
they mustn't be lessening	I mustn't have lessened
you mustn't have lessened
she mustn't have lessened
we mustn't have lessened
you mustn't have lessened
they mustn't have lessened	I mustn't have been lessening
you mustn't have been lessening
she mustn't have been lessening
we mustn't have been lessening
you mustn't have been lessening
they mustn't have been lessening	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I lessen?
must you lessen?
must she lessen?
must we lessen?
must you lessen?
must they lessen? 	must I be lessening?
must you be lessening?
must she be lessening?
must we be lessening?
must you be lessening?
must they be lessening? 	must I have lessened?
must you have lessened?
must she have lessened?
must we have lessened?
must you have lessened?
must they have lessened? 	must I have been lessening?
must you have been lessening?
must she have been lessening?
must we have been lessening?
must you have been lessening?
must they have been lessening? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
mustn't I lessen?
mustn't you lessen?
mustn't she lessen?
mustn't we lessen?
mustn't you lessen?
mustn't they lessen? 	mustn't I be lessening?
mustn't you be lessening?
mustn't she be lessening?
mustn't we be lessening?
mustn't you be lessening?
mustn't they be lessening? 	mustn't I have lessened?
mustn't you have lessened?
mustn't she have lessened?
mustn't we have lessened?
mustn't you have lessened?
mustn't they have lessened? 	mustn't I have been lessening?
mustn't you have been lessening?
mustn't she have been lessening?
mustn't we have been lessening?
mustn't you have been lessening?
mustn't they have been lessening?