can dumb
Regular verb: dumb - dumbed- dumbed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can dumb
you can dumb
she can dumb
we can dumb
you can dumb
they can dumb 	I can be dumbing
you can be dumbing
she can be dumbing
we can be dumbing
you can be dumbing
they can be dumbing	I can have dumbed
you can have dumbed
she can have dumbed
we can have dumbed
you can have dumbed
they can have dumbed	I can have been dumbing
you can have been dumbing
she can have been dumbing
we can have been dumbing
you can have been dumbing
they can have been dumbing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't dumb
you can't dumb
she can't dumb
we can't dumb
you can't dumb
they can't dumb 	I can't be dumbing
you can't be dumbing
she can't be dumbing
we can't be dumbing
you can't be dumbing
they can't be dumbing	I can't have dumbed
you can't have dumbed
she can't have dumbed
we can't have dumbed
you can't have dumbed
they can't have dumbed	I can't have been dumbing
you can't have been dumbing
she can't have been dumbing
we can't have been dumbing
you can't have been dumbing
they can't have been dumbing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I dumb?
can you dumb?
can she dumb?
can we dumb?
can you dumb?
can they dumb? 	can I be dumbing?
can you be dumbing?
can she be dumbing?
can we be dumbing?
can you be dumbing?
can they be dumbing? 	can I have dumbed?
can you have dumbed?
can she have dumbed?
can we have dumbed?
can you have dumbed?
can they have dumbed? 	can I have been dumbing?
can you have been dumbing?
can she have been dumbing?
can we have been dumbing?
can you have been dumbing?
can they have been dumbing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I dumb?
can't you dumb?
can't she dumb?
can't we dumb?
can't you dumb?
can't they dumb? 	can't I be dumbing?
can't you be dumbing?
can't she be dumbing?
can't we be dumbing?
can't you be dumbing?
can't they be dumbing? 	can't I have dumbed?
can't you have dumbed?
can't she have dumbed?
can't we have dumbed?
can't you have dumbed?
can't they have dumbed? 	can't I have been dumbing?
can't you have been dumbing?
can't she have been dumbing?
can't we have been dumbing?
can't you have been dumbing?
can't they have been dumbing?