must concertina
Regular verb: concertina - concertinaed- concertinaed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must concertina
you must concertina
she must concertina
we must concertina
you must concertina
they must concertina 	I must be concertinaing
you must be concertinaing
she must be concertinaing
we must be concertinaing
you must be concertinaing
they must be concertinaing	I must have concertinaed
you must have concertinaed
she must have concertinaed
we must have concertinaed
you must have concertinaed
they must have concertinaed	I must have been concertinaing
you must have been concertinaing
she must have been concertinaing
we must have been concertinaing
you must have been concertinaing
they must have been concertinaing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not concertina
you must not concertina
she must not concertina
we must not concertina
you must not concertina
they must not concertina 	I must not be concertinaing
you must not be concertinaing
she must not be concertinaing
we must not be concertinaing
you must not be concertinaing
they must not be concertinaing	I must not have concertinaed
you must not have concertinaed
she must not have concertinaed
we must not have concertinaed
you must not have concertinaed
they must not have concertinaed	I must not have been concertinaing
you must not have been concertinaing
she must not have been concertinaing
we must not have been concertinaing
you must not have been concertinaing
they must not have been concertinaing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I concertina?
must you concertina?
must she concertina?
must we concertina?
must you concertina?
must they concertina? 	must I be concertinaing?
must you be concertinaing?
must she be concertinaing?
must we be concertinaing?
must you be concertinaing?
must they be concertinaing? 	must I have concertinaed?
must you have concertinaed?
must she have concertinaed?
must we have concertinaed?
must you have concertinaed?
must they have concertinaed? 	must I have been concertinaing?
must you have been concertinaing?
must she have been concertinaing?
must we have been concertinaing?
must you have been concertinaing?
must they have been concertinaing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not concertina?
must you not concertina?
must she not concertina?
must we not concertina?
must you not concertina?
must they not concertina? 	must I not be concertinaing?
must you not be concertinaing?
must she not be concertinaing?
must we not be concertinaing?
must you not be concertinaing?
must they not be concertinaing? 	must I not have concertinaed?
must you not have concertinaed?
must she not have concertinaed?
must we not have concertinaed?
must you not have concertinaed?
must they not have concertinaed? 	must I not have been concertinaing?
must you not have been concertinaing?
must she not have been concertinaing?
must we not have been concertinaing?
must you not have been concertinaing?
must they not have been concertinaing?