must trepan
Regular verb: trepan - trepanned- trepanned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must trepan
you must trepan
he must trepan
we must trepan
you must trepan
they must trepan 	I must be trepanning
you must be trepanning
he must be trepanning
we must be trepanning
you must be trepanning
they must be trepanning	I must have trepanned
you must have trepanned
he must have trepanned
we must have trepanned
you must have trepanned
they must have trepanned	I must have been trepanning
you must have been trepanning
he must have been trepanning
we must have been trepanning
you must have been trepanning
they must have been trepanning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't trepan
you mustn't trepan
he mustn't trepan
we mustn't trepan
you mustn't trepan
they mustn't trepan 	I mustn't be trepanning
you mustn't be trepanning
he mustn't be trepanning
we mustn't be trepanning
you mustn't be trepanning
they mustn't be trepanning	I mustn't have trepanned
you mustn't have trepanned
he mustn't have trepanned
we mustn't have trepanned
you mustn't have trepanned
they mustn't have trepanned	I mustn't have been trepanning
you mustn't have been trepanning
he mustn't have been trepanning
we mustn't have been trepanning
you mustn't have been trepanning
they mustn't have been trepanning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I trepan?
must you trepan?
must he trepan?
must we trepan?
must you trepan?
must they trepan? 	must I be trepanning?
must you be trepanning?
must he be trepanning?
must we be trepanning?
must you be trepanning?
must they be trepanning? 	must I have trepanned?
must you have trepanned?
must he have trepanned?
must we have trepanned?
must you have trepanned?
must they have trepanned? 	must I have been trepanning?
must you have been trepanning?
must he have been trepanning?
must we have been trepanning?
must you have been trepanning?
must they have been trepanning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I trepan?
mustn't you trepan?
mustn't he trepan?
mustn't we trepan?
mustn't you trepan?
mustn't they trepan? 	mustn't I be trepanning?
mustn't you be trepanning?
mustn't he be trepanning?
mustn't we be trepanning?
mustn't you be trepanning?
mustn't they be trepanning? 	mustn't I have trepanned?
mustn't you have trepanned?
mustn't he have trepanned?
mustn't we have trepanned?
mustn't you have trepanned?
mustn't they have trepanned? 	mustn't I have been trepanning?
mustn't you have been trepanning?
mustn't he have been trepanning?
mustn't we have been trepanning?
mustn't you have been trepanning?
mustn't they have been trepanning?