can keen
Regular verb: keen - keened- keened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can keen
you can keen
he can keen
we can keen
you can keen
they can keen 	I can be keening
you can be keening
he can be keening
we can be keening
you can be keening
they can be keening	I can have keened
you can have keened
he can have keened
we can have keened
you can have keened
they can have keened	I can have been keening
you can have been keening
he can have been keening
we can have been keening
you can have been keening
they can have been keening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't keen
you can't keen
he can't keen
we can't keen
you can't keen
they can't keen 	I can't be keening
you can't be keening
he can't be keening
we can't be keening
you can't be keening
they can't be keening	I can't have keened
you can't have keened
he can't have keened
we can't have keened
you can't have keened
they can't have keened	I can't have been keening
you can't have been keening
he can't have been keening
we can't have been keening
you can't have been keening
they can't have been keening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I keen?
can you keen?
can he keen?
can we keen?
can you keen?
can they keen? 	can I be keening?
can you be keening?
can he be keening?
can we be keening?
can you be keening?
can they be keening? 	can I have keened?
can you have keened?
can he have keened?
can we have keened?
can you have keened?
can they have keened? 	can I have been keening?
can you have been keening?
can he have been keening?
can we have been keening?
can you have been keening?
can they have been keening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I keen?
can't you keen?
can't he keen?
can't we keen?
can't you keen?
can't they keen? 	can't I be keening?
can't you be keening?
can't he be keening?
can't we be keening?
can't you be keening?
can't they be keening? 	can't I have keened?
can't you have keened?
can't he have keened?
can't we have keened?
can't you have keened?
can't they have keened? 	can't I have been keening?
can't you have been keening?
can't he have been keening?
can't we have been keening?
can't you have been keening?
can't they have been keening?