must fasten
Verbo regular: fasten - fastened- fastened

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must fasten
you must fasten
he must fasten
we must fasten
you must fasten
they must fasten 	I must be fastening
you must be fastening
he must be fastening
we must be fastening
you must be fastening
they must be fastening	I must have fastened
you must have fastened
he must have fastened
we must have fastened
you must have fastened
they must have fastened	I must have been fastening
you must have been fastening
he must have been fastening
we must have been fastening
you must have been fastening
they must have been fastening	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not fasten
you must not fasten
he must not fasten
we must not fasten
you must not fasten
they must not fasten 	I must not be fastening
you must not be fastening
he must not be fastening
we must not be fastening
you must not be fastening
they must not be fastening	I must not have fastened
you must not have fastened
he must not have fastened
we must not have fastened
you must not have fastened
they must not have fastened	I must not have been fastening
you must not have been fastening
he must not have been fastening
we must not have been fastening
you must not have been fastening
they must not have been fastening	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I fasten?
must you fasten?
must he fasten?
must we fasten?
must you fasten?
must they fasten? 	must I be fastening?
must you be fastening?
must he be fastening?
must we be fastening?
must you be fastening?
must they be fastening? 	must I have fastened?
must you have fastened?
must he have fastened?
must we have fastened?
must you have fastened?
must they have fastened? 	must I have been fastening?
must you have been fastening?
must he have been fastening?
must we have been fastening?
must you have been fastening?
must they have been fastening? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not fasten?
must you not fasten?
must he not fasten?
must we not fasten?
must you not fasten?
must they not fasten? 	must I not be fastening?
must you not be fastening?
must he not be fastening?
must we not be fastening?
must you not be fastening?
must they not be fastening? 	must I not have fastened?
must you not have fastened?
must he not have fastened?
must we not have fastened?
must you not have fastened?
must they not have fastened? 	must I not have been fastening?
must you not have been fastening?
must he not have been fastening?
must we not have been fastening?
must you not have been fastening?
must they not have been fastening?