can concuss
Regular verb: concuss - concussed- concussed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can concuss
you can concuss
he can concuss
we can concuss
you can concuss
they can concuss 	I can be concussing
you can be concussing
he can be concussing
we can be concussing
you can be concussing
they can be concussing	I can have concussed
you can have concussed
he can have concussed
we can have concussed
you can have concussed
they can have concussed	I can have been concussing
you can have been concussing
he can have been concussing
we can have been concussing
you can have been concussing
they can have been concussing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't concuss
you can't concuss
he can't concuss
we can't concuss
you can't concuss
they can't concuss 	I can't be concussing
you can't be concussing
he can't be concussing
we can't be concussing
you can't be concussing
they can't be concussing	I can't have concussed
you can't have concussed
he can't have concussed
we can't have concussed
you can't have concussed
they can't have concussed	I can't have been concussing
you can't have been concussing
he can't have been concussing
we can't have been concussing
you can't have been concussing
they can't have been concussing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I concuss?
can you concuss?
can he concuss?
can we concuss?
can you concuss?
can they concuss? 	can I be concussing?
can you be concussing?
can he be concussing?
can we be concussing?
can you be concussing?
can they be concussing? 	can I have concussed?
can you have concussed?
can he have concussed?
can we have concussed?
can you have concussed?
can they have concussed? 	can I have been concussing?
can you have been concussing?
can he have been concussing?
can we have been concussing?
can you have been concussing?
can they have been concussing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I concuss?
can't you concuss?
can't he concuss?
can't we concuss?
can't you concuss?
can't they concuss? 	can't I be concussing?
can't you be concussing?
can't he be concussing?
can't we be concussing?
can't you be concussing?
can't they be concussing? 	can't I have concussed?
can't you have concussed?
can't he have concussed?
can't we have concussed?
can't you have concussed?
can't they have concussed? 	can't I have been concussing?
can't you have been concussing?
can't he have been concussing?
can't we have been concussing?
can't you have been concussing?
can't they have been concussing?