must toughen
Verbo regolare: toughen - toughened- toughened

Affermazione 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
I must toughen
you must toughen
he must toughen
we must toughen
you must toughen
they must toughen 	I must be toughening
you must be toughening
he must be toughening
we must be toughening
you must be toughening
they must be toughening	I must have toughened
you must have toughened
he must have toughened
we must have toughened
you must have toughened
they must have toughened	I must have been toughening
you must have been toughening
he must have been toughening
we must have been toughening
you must have been toughening
they must have been toughening	

Negazione 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
I must not toughen
you must not toughen
he must not toughen
we must not toughen
you must not toughen
they must not toughen 	I must not be toughening
you must not be toughening
he must not be toughening
we must not be toughening
you must not be toughening
they must not be toughening	I must not have toughened
you must not have toughened
he must not have toughened
we must not have toughened
you must not have toughened
they must not have toughened	I must not have been toughening
you must not have been toughening
he must not have been toughening
we must not have been toughening
you must not have been toughening
they must not have been toughening	

Forma interrogativa 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
must I toughen?
must you toughen?
must he toughen?
must we toughen?
must you toughen?
must they toughen? 	must I be toughening?
must you be toughening?
must he be toughening?
must we be toughening?
must you be toughening?
must they be toughening? 	must I have toughened?
must you have toughened?
must he have toughened?
must we have toughened?
must you have toughened?
must they have toughened? 	must I have been toughening?
must you have been toughening?
must he have been toughening?
must we have been toughening?
must you have been toughening?
must they have been toughening? 	

Forma interro-negativa 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
must I not toughen?
must you not toughen?
must he not toughen?
must we not toughen?
must you not toughen?
must they not toughen? 	must I not be toughening?
must you not be toughening?
must he not be toughening?
must we not be toughening?
must you not be toughening?
must they not be toughening? 	must I not have toughened?
must you not have toughened?
must he not have toughened?
must we not have toughened?
must you not have toughened?
must they not have toughened? 	must I not have been toughening?
must you not have been toughening?
must he not have been toughening?
must we not have been toughening?
must you not have been toughening?
must they not have been toughening?