must harshen
Regular verb: harshen - harshened- harshened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must harshen
you must harshen
he must harshen
we must harshen
you must harshen
they must harshen 	I must be harshening
you must be harshening
he must be harshening
we must be harshening
you must be harshening
they must be harshening	I must have harshened
you must have harshened
he must have harshened
we must have harshened
you must have harshened
they must have harshened	I must have been harshening
you must have been harshening
he must have been harshening
we must have been harshening
you must have been harshening
they must have been harshening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't harshen
you mustn't harshen
he mustn't harshen
we mustn't harshen
you mustn't harshen
they mustn't harshen 	I mustn't be harshening
you mustn't be harshening
he mustn't be harshening
we mustn't be harshening
you mustn't be harshening
they mustn't be harshening	I mustn't have harshened
you mustn't have harshened
he mustn't have harshened
we mustn't have harshened
you mustn't have harshened
they mustn't have harshened	I mustn't have been harshening
you mustn't have been harshening
he mustn't have been harshening
we mustn't have been harshening
you mustn't have been harshening
they mustn't have been harshening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I harshen?
must you harshen?
must he harshen?
must we harshen?
must you harshen?
must they harshen? 	must I be harshening?
must you be harshening?
must he be harshening?
must we be harshening?
must you be harshening?
must they be harshening? 	must I have harshened?
must you have harshened?
must he have harshened?
must we have harshened?
must you have harshened?
must they have harshened? 	must I have been harshening?
must you have been harshening?
must he have been harshening?
must we have been harshening?
must you have been harshening?
must they have been harshening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I harshen?
mustn't you harshen?
mustn't he harshen?
mustn't we harshen?
mustn't you harshen?
mustn't they harshen? 	mustn't I be harshening?
mustn't you be harshening?
mustn't he be harshening?
mustn't we be harshening?
mustn't you be harshening?
mustn't they be harshening? 	mustn't I have harshened?
mustn't you have harshened?
mustn't he have harshened?
mustn't we have harshened?
mustn't you have harshened?
mustn't they have harshened? 	mustn't I have been harshening?
mustn't you have been harshening?
mustn't he have been harshening?
mustn't we have been harshening?
mustn't you have been harshening?
mustn't they have been harshening?