must calender
Regular verb: calender - calendered- calendered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must calender
you must calender
he must calender
we must calender
you must calender
they must calender 	I must be calendering
you must be calendering
he must be calendering
we must be calendering
you must be calendering
they must be calendering	I must have calendered
you must have calendered
he must have calendered
we must have calendered
you must have calendered
they must have calendered	I must have been calendering
you must have been calendering
he must have been calendering
we must have been calendering
you must have been calendering
they must have been calendering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't calender
you mustn't calender
he mustn't calender
we mustn't calender
you mustn't calender
they mustn't calender 	I mustn't be calendering
you mustn't be calendering
he mustn't be calendering
we mustn't be calendering
you mustn't be calendering
they mustn't be calendering	I mustn't have calendered
you mustn't have calendered
he mustn't have calendered
we mustn't have calendered
you mustn't have calendered
they mustn't have calendered	I mustn't have been calendering
you mustn't have been calendering
he mustn't have been calendering
we mustn't have been calendering
you mustn't have been calendering
they mustn't have been calendering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I calender?
must you calender?
must he calender?
must we calender?
must you calender?
must they calender? 	must I be calendering?
must you be calendering?
must he be calendering?
must we be calendering?
must you be calendering?
must they be calendering? 	must I have calendered?
must you have calendered?
must he have calendered?
must we have calendered?
must you have calendered?
must they have calendered? 	must I have been calendering?
must you have been calendering?
must he have been calendering?
must we have been calendering?
must you have been calendering?
must they have been calendering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I calender?
mustn't you calender?
mustn't he calender?
mustn't we calender?
mustn't you calender?
mustn't they calender? 	mustn't I be calendering?
mustn't you be calendering?
mustn't he be calendering?
mustn't we be calendering?
mustn't you be calendering?
mustn't they be calendering? 	mustn't I have calendered?
mustn't you have calendered?
mustn't he have calendered?
mustn't we have calendered?
mustn't you have calendered?
mustn't they have calendered? 	mustn't I have been calendering?
mustn't you have been calendering?
mustn't he have been calendering?
mustn't we have been calendering?
mustn't you have been calendering?
mustn't they have been calendering?