can dun
Regular verb: dun - dunned- dunned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can dun
you can dun
he can dun
we can dun
you can dun
they can dun 	I can be dunning
you can be dunning
he can be dunning
we can be dunning
you can be dunning
they can be dunning	I can have dunned
you can have dunned
he can have dunned
we can have dunned
you can have dunned
they can have dunned	I can have been dunning
you can have been dunning
he can have been dunning
we can have been dunning
you can have been dunning
they can have been dunning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't dun
you can't dun
he can't dun
we can't dun
you can't dun
they can't dun 	I can't be dunning
you can't be dunning
he can't be dunning
we can't be dunning
you can't be dunning
they can't be dunning	I can't have dunned
you can't have dunned
he can't have dunned
we can't have dunned
you can't have dunned
they can't have dunned	I can't have been dunning
you can't have been dunning
he can't have been dunning
we can't have been dunning
you can't have been dunning
they can't have been dunning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I dun?
can you dun?
can he dun?
can we dun?
can you dun?
can they dun? 	can I be dunning?
can you be dunning?
can he be dunning?
can we be dunning?
can you be dunning?
can they be dunning? 	can I have dunned?
can you have dunned?
can he have dunned?
can we have dunned?
can you have dunned?
can they have dunned? 	can I have been dunning?
can you have been dunning?
can he have been dunning?
can we have been dunning?
can you have been dunning?
can they have been dunning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I dun?
can't you dun?
can't he dun?
can't we dun?
can't you dun?
can't they dun? 	can't I be dunning?
can't you be dunning?
can't he be dunning?
can't we be dunning?
can't you be dunning?
can't they be dunning? 	can't I have dunned?
can't you have dunned?
can't he have dunned?
can't we have dunned?
can't you have dunned?
can't they have dunned? 	can't I have been dunning?
can't you have been dunning?
can't he have been dunning?
can't we have been dunning?
can't you have been dunning?
can't they have been dunning?