must ruff
Verbo regular: ruff - ruffed- ruffed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must ruff
you must ruff
she must ruff
we must ruff
you must ruff
they must ruff 	I must be ruffing
you must be ruffing
she must be ruffing
we must be ruffing
you must be ruffing
they must be ruffing	I must have ruffed
you must have ruffed
she must have ruffed
we must have ruffed
you must have ruffed
they must have ruffed	I must have been ruffing
you must have been ruffing
she must have been ruffing
we must have been ruffing
you must have been ruffing
they must have been ruffing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not ruff
you must not ruff
she must not ruff
we must not ruff
you must not ruff
they must not ruff 	I must not be ruffing
you must not be ruffing
she must not be ruffing
we must not be ruffing
you must not be ruffing
they must not be ruffing	I must not have ruffed
you must not have ruffed
she must not have ruffed
we must not have ruffed
you must not have ruffed
they must not have ruffed	I must not have been ruffing
you must not have been ruffing
she must not have been ruffing
we must not have been ruffing
you must not have been ruffing
they must not have been ruffing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I ruff?
must you ruff?
must she ruff?
must we ruff?
must you ruff?
must they ruff? 	must I be ruffing?
must you be ruffing?
must she be ruffing?
must we be ruffing?
must you be ruffing?
must they be ruffing? 	must I have ruffed?
must you have ruffed?
must she have ruffed?
must we have ruffed?
must you have ruffed?
must they have ruffed? 	must I have been ruffing?
must you have been ruffing?
must she have been ruffing?
must we have been ruffing?
must you have been ruffing?
must they have been ruffing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not ruff?
must you not ruff?
must she not ruff?
must we not ruff?
must you not ruff?
must they not ruff? 	must I not be ruffing?
must you not be ruffing?
must she not be ruffing?
must we not be ruffing?
must you not be ruffing?
must they not be ruffing? 	must I not have ruffed?
must you not have ruffed?
must she not have ruffed?
must we not have ruffed?
must you not have ruffed?
must they not have ruffed? 	must I not have been ruffing?
must you not have been ruffing?
must she not have been ruffing?
must we not have been ruffing?
must you not have been ruffing?
must they not have been ruffing?