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 mustn't concertina
you mustn't concertina
she mustn't concertina
we mustn't concertina
you mustn't concertina
they mustn't concertina 	I mustn't be concertinaing
you mustn't be concertinaing
she mustn't be concertinaing
we mustn't be concertinaing
you mustn't be concertinaing
they mustn't be concertinaing	I mustn't have concertinaed
you mustn't have concertinaed
she mustn't have concertinaed
we mustn't have concertinaed
you mustn't have concertinaed
they mustn't have concertinaed	I mustn't have been concertinaing
you mustn't have been concertinaing
she mustn't have been concertinaing
we mustn't have been concertinaing
you mustn't have been concertinaing
they mustn't 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 	
mustn't I concertina?
mustn't you concertina?
mustn't she concertina?
mustn't we concertina?
mustn't you concertina?
mustn't they concertina? 	mustn't I be concertinaing?
mustn't you be concertinaing?
mustn't she be concertinaing?
mustn't we be concertinaing?
mustn't you be concertinaing?
mustn't they be concertinaing? 	mustn't I have concertinaed?
mustn't you have concertinaed?
mustn't she have concertinaed?
mustn't we have concertinaed?
mustn't you have concertinaed?
mustn't they have concertinaed? 	mustn't I have been concertinaing?
mustn't you have been concertinaing?
mustn't she have been concertinaing?
mustn't we have been concertinaing?
mustn't you have been concertinaing?
mustn't they have been concertinaing?