could keen
Regular verb: keen - keened- keened

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

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

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

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