must sign
Verbo regular: sign - signed- signed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con 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	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not sign
you must not sign
he must not sign
we must not sign
you must not sign
they must not sign 	I must not be signing
you must not be signing
he must not be signing
we must not be signing
you must not be signing
they must not be signing	I must not have signed
you must not have signed
he must not have signed
we must not have signed
you must not have signed
they must not have signed	I must not have been signing
you must not have been signing
he must not have been signing
we must not have been signing
you must not have been signing
they must not have been signing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con 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-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not sign?
must you not sign?
must he not sign?
must we not sign?
must you not sign?
must they not sign? 	must I not be signing?
must you not be signing?
must he not be signing?
must we not be signing?
must you not be signing?
must they not be signing? 	must I not have signed?
must you not have signed?
must he not have signed?
must we not have signed?
must you not have signed?
must they not have signed? 	must I not have been signing?
must you not have been signing?
must he not have been signing?
must we not have been signing?
must you not have been signing?
must they not have been signing?