must sign
Verbo regular: sign - signed- signed

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must sign
you must sign
he must sign
we must sign
you must sign
they must sign 	I must be signing
you must be signing
he must be signing
we must be signing
you must be signing
they must be signing	I must have signed
you must have signed
he must have signed
we must have signed
you must have signed
they must have signed	I must have been signing
you must have been signing
he must have been signing
we must have been signing
you must have been signing
they must have been signing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I mustn't sign
you mustn't sign
he mustn't sign
we mustn't sign
you mustn't sign
they mustn't sign 	I mustn't be signing
you mustn't be signing
he mustn't be signing
we mustn't be signing
you mustn't be signing
they mustn't be signing	I mustn't have signed
you mustn't have signed
he mustn't have signed
we mustn't have signed
you mustn't have signed
they mustn't have signed	I mustn't have been signing
you mustn't have been signing
he mustn't have been signing
we mustn't have been signing
you mustn't have been signing
they mustn't have been signing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I sign?
must you sign?
must he sign?
must we sign?
must you sign?
must they sign? 	must I be signing?
must you be signing?
must he be signing?
must we be signing?
must you be signing?
must they be signing? 	must I have signed?
must you have signed?
must he have signed?
must we have signed?
must you have signed?
must they have signed? 	must I have been signing?
must you have been signing?
must he have been signing?
must we have been signing?
must you have been signing?
must they have been signing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
mustn't I sign?
mustn't you sign?
mustn't he sign?
mustn't we sign?
mustn't you sign?
mustn't they sign? 	mustn't I be signing?
mustn't you be signing?
mustn't he be signing?
mustn't we be signing?
mustn't you be signing?
mustn't they be signing? 	mustn't I have signed?
mustn't you have signed?
mustn't he have signed?
mustn't we have signed?
mustn't you have signed?
mustn't they have signed? 	mustn't I have been signing?
mustn't you have been signing?
mustn't he have been signing?
mustn't we have been signing?
mustn't you have been signing?
mustn't they have been signing?