must rib
Verbo regular: rib - ribed- ribed

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must rib
you must rib
he must rib
we must rib
you must rib
they must rib 	I must be ribing
you must be ribing
he must be ribing
we must be ribing
you must be ribing
they must be ribing	I must have ribed
you must have ribed
he must have ribed
we must have ribed
you must have ribed
they must have ribed	I must have been ribing
you must have been ribing
he must have been ribing
we must have been ribing
you must have been ribing
they must have been ribing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I mustn't rib
you mustn't rib
he mustn't rib
we mustn't rib
you mustn't rib
they mustn't rib 	I mustn't be ribing
you mustn't be ribing
he mustn't be ribing
we mustn't be ribing
you mustn't be ribing
they mustn't be ribing	I mustn't have ribed
you mustn't have ribed
he mustn't have ribed
we mustn't have ribed
you mustn't have ribed
they mustn't have ribed	I mustn't have been ribing
you mustn't have been ribing
he mustn't have been ribing
we mustn't have been ribing
you mustn't have been ribing
they mustn't have been ribing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I rib?
must you rib?
must he rib?
must we rib?
must you rib?
must they rib? 	must I be ribing?
must you be ribing?
must he be ribing?
must we be ribing?
must you be ribing?
must they be ribing? 	must I have ribed?
must you have ribed?
must he have ribed?
must we have ribed?
must you have ribed?
must they have ribed? 	must I have been ribing?
must you have been ribing?
must he have been ribing?
must we have been ribing?
must you have been ribing?
must they have been ribing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
mustn't I rib?
mustn't you rib?
mustn't he rib?
mustn't we rib?
mustn't you rib?
mustn't they rib? 	mustn't I be ribing?
mustn't you be ribing?
mustn't he be ribing?
mustn't we be ribing?
mustn't you be ribing?
mustn't they be ribing? 	mustn't I have ribed?
mustn't you have ribed?
mustn't he have ribed?
mustn't we have ribed?
mustn't you have ribed?
mustn't they have ribed? 	mustn't I have been ribing?
mustn't you have been ribing?
mustn't he have been ribing?
mustn't we have been ribing?
mustn't you have been ribing?
mustn't they have been ribing?