must grind
Verbo irregular: grind - ground- ground

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must grind
you must grind
he must grind
we must grind
you must grind
they must grind 	I must be grinding
you must be grinding
he must be grinding
we must be grinding
you must be grinding
they must be grinding	I must have ground
you must have ground
he must have ground
we must have ground
you must have ground
they must have ground	I must have been grinding
you must have been grinding
he must have been grinding
we must have been grinding
you must have been grinding
they must have been grinding	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not grind
you must not grind
he must not grind
we must not grind
you must not grind
they must not grind 	I must not be grinding
you must not be grinding
he must not be grinding
we must not be grinding
you must not be grinding
they must not be grinding	I must not have ground
you must not have ground
he must not have ground
we must not have ground
you must not have ground
they must not have ground	I must not have been grinding
you must not have been grinding
he must not have been grinding
we must not have been grinding
you must not have been grinding
they must not have been grinding	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I grind?
must you grind?
must he grind?
must we grind?
must you grind?
must they grind? 	must I be grinding?
must you be grinding?
must he be grinding?
must we be grinding?
must you be grinding?
must they be grinding? 	must I have ground?
must you have ground?
must he have ground?
must we have ground?
must you have ground?
must they have ground? 	must I have been grinding?
must you have been grinding?
must he have been grinding?
must we have been grinding?
must you have been grinding?
must they have been grinding? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not grind?
must you not grind?
must he not grind?
must we not grind?
must you not grind?
must they not grind? 	must I not be grinding?
must you not be grinding?
must he not be grinding?
must we not be grinding?
must you not be grinding?
must they not be grinding? 	must I not have ground?
must you not have ground?
must he not have ground?
must we not have ground?
must you not have ground?
must they not have ground? 	must I not have been grinding?
must you not have been grinding?
must he not have been grinding?
must we not have been grinding?
must you not have been grinding?
must they not have been grinding?