must tighten
Verbo regular: tighten - tightened- tightened

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must tighten
you must tighten
he must tighten
we must tighten
you must tighten
they must tighten 	I must be tightening
you must be tightening
he must be tightening
we must be tightening
you must be tightening
they must be tightening	I must have tightened
you must have tightened
he must have tightened
we must have tightened
you must have tightened
they must have tightened	I must have been tightening
you must have been tightening
he must have been tightening
we must have been tightening
you must have been tightening
they must have been tightening	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not tighten
you must not tighten
he must not tighten
we must not tighten
you must not tighten
they must not tighten 	I must not be tightening
you must not be tightening
he must not be tightening
we must not be tightening
you must not be tightening
they must not be tightening	I must not have tightened
you must not have tightened
he must not have tightened
we must not have tightened
you must not have tightened
they must not have tightened	I must not have been tightening
you must not have been tightening
he must not have been tightening
we must not have been tightening
you must not have been tightening
they must not have been tightening	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I tighten?
must you tighten?
must he tighten?
must we tighten?
must you tighten?
must they tighten? 	must I be tightening?
must you be tightening?
must he be tightening?
must we be tightening?
must you be tightening?
must they be tightening? 	must I have tightened?
must you have tightened?
must he have tightened?
must we have tightened?
must you have tightened?
must they have tightened? 	must I have been tightening?
must you have been tightening?
must he have been tightening?
must we have been tightening?
must you have been tightening?
must they have been tightening? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not tighten?
must you not tighten?
must he not tighten?
must we not tighten?
must you not tighten?
must they not tighten? 	must I not be tightening?
must you not be tightening?
must he not be tightening?
must we not be tightening?
must you not be tightening?
must they not be tightening? 	must I not have tightened?
must you not have tightened?
must he not have tightened?
must we not have tightened?
must you not have tightened?
must they not have tightened? 	must I not have been tightening?
must you not have been tightening?
must he not have been tightening?
must we not have been tightening?
must you not have been tightening?
must they not have been tightening?