can concertina
Regular verb: concertina - concertinaed- concertinaed

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

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't concertina
you can't concertina
he can't concertina
we can't concertina
you can't concertina
they can't concertina 	I can't be concertinaing
you can't be concertinaing
he can't be concertinaing
we can't be concertinaing
you can't be concertinaing
they can't be concertinaing	I can't have concertinaed
you can't have concertinaed
he can't have concertinaed
we can't have concertinaed
you can't have concertinaed
they can't have concertinaed	I can't have been concertinaing
you can't have been concertinaing
he can't have been concertinaing
we can't have been concertinaing
you can't have been concertinaing
they can't have been concertinaing	

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

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I concertina?
can't you concertina?
can't he concertina?
can't we concertina?
can't you concertina?
can't they concertina? 	can't I be concertinaing?
can't you be concertinaing?
can't he be concertinaing?
can't we be concertinaing?
can't you be concertinaing?
can't they be concertinaing? 	can't I have concertinaed?
can't you have concertinaed?
can't he have concertinaed?
can't we have concertinaed?
can't you have concertinaed?
can't they have concertinaed? 	can't I have been concertinaing?
can't you have been concertinaing?
can't he have been concertinaing?
can't we have been concertinaing?
can't you have been concertinaing?
can't they have been concertinaing?