must dull
Verbo regular: dull - dulled- dulled

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must dull
you must dull
she must dull
we must dull
you must dull
they must dull 	I must be dulling
you must be dulling
she must be dulling
we must be dulling
you must be dulling
they must be dulling	I must have dulled
you must have dulled
she must have dulled
we must have dulled
you must have dulled
they must have dulled	I must have been dulling
you must have been dulling
she must have been dulling
we must have been dulling
you must have been dulling
they must have been dulling	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I mustn't dull
you mustn't dull
she mustn't dull
we mustn't dull
you mustn't dull
they mustn't dull 	I mustn't be dulling
you mustn't be dulling
she mustn't be dulling
we mustn't be dulling
you mustn't be dulling
they mustn't be dulling	I mustn't have dulled
you mustn't have dulled
she mustn't have dulled
we mustn't have dulled
you mustn't have dulled
they mustn't have dulled	I mustn't have been dulling
you mustn't have been dulling
she mustn't have been dulling
we mustn't have been dulling
you mustn't have been dulling
they mustn't have been dulling	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I dull?
must you dull?
must she dull?
must we dull?
must you dull?
must they dull? 	must I be dulling?
must you be dulling?
must she be dulling?
must we be dulling?
must you be dulling?
must they be dulling? 	must I have dulled?
must you have dulled?
must she have dulled?
must we have dulled?
must you have dulled?
must they have dulled? 	must I have been dulling?
must you have been dulling?
must she have been dulling?
must we have been dulling?
must you have been dulling?
must they have been dulling? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
mustn't I dull?
mustn't you dull?
mustn't she dull?
mustn't we dull?
mustn't you dull?
mustn't they dull? 	mustn't I be dulling?
mustn't you be dulling?
mustn't she be dulling?
mustn't we be dulling?
mustn't you be dulling?
mustn't they be dulling? 	mustn't I have dulled?
mustn't you have dulled?
mustn't she have dulled?
mustn't we have dulled?
mustn't you have dulled?
mustn't they have dulled? 	mustn't I have been dulling?
mustn't you have been dulling?
mustn't she have been dulling?
mustn't we have been dulling?
mustn't you have been dulling?
mustn't they have been dulling?