must calender
Regular verb: calender - calendered- calendered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must calender
you must calender
she must calender
we must calender
you must calender
they must calender 	I must be calendering
you must be calendering
she must be calendering
we must be calendering
you must be calendering
they must be calendering	I must have calendered
you must have calendered
she 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
she 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 must not calender
you must not calender
she must not calender
we must not calender
you must not calender
they must not calender 	I must not be calendering
you must not be calendering
she must not be calendering
we must not be calendering
you must not be calendering
they must not be calendering	I must not have calendered
you must not have calendered
she must not have calendered
we must not have calendered
you must not have calendered
they must not have calendered	I must not have been calendering
you must not have been calendering
she must not have been calendering
we must not have been calendering
you must not have been calendering
they must not have been calendering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I calender?
must you calender?
must she calender?
must we calender?
must you calender?
must they calender? 	must I be calendering?
must you be calendering?
must she be calendering?
must we be calendering?
must you be calendering?
must they be calendering? 	must I have calendered?
must you have calendered?
must she 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 she 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 	
must I not calender?
must you not calender?
must she not calender?
must we not calender?
must you not calender?
must they not calender? 	must I not be calendering?
must you not be calendering?
must she not be calendering?
must we not be calendering?
must you not be calendering?
must they not be calendering? 	must I not have calendered?
must you not have calendered?
must she not have calendered?
must we not have calendered?
must you not have calendered?
must they not have calendered? 	must I not have been calendering?
must you not have been calendering?
must she not have been calendering?
must we not have been calendering?
must you not have been calendering?
must they not have been calendering?