I can keen you can keen he can keen we can keen you can keen they can keen
V-ing form
I can be keening you can be keening he can be keening we can be keening you can be keening they can be keening
Perfect
I can have keened you can have keened he can have keened we can have keened you can have keened they can have keened
V-ing perfect
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
I cannot keen you cannot keen he cannot keen we cannot keen you cannot keen they cannot keen
V-ing form
I cannot be keening you cannot be keening he cannot be keening we cannot be keening you cannot be keening they cannot be keening
Perfect
I cannot have keened you cannot have keened he cannot have keened we cannot have keened you cannot have keened they cannot have keened
V-ing perfect
I cannot have been keening you cannot have been keening he cannot have been keening we cannot have been keening you cannot have been keening they cannot have been keening
Interrogative form
Simple form
can I keen? can you keen? can he keen? can we keen? can you keen? can they keen?
V-ing form
can I be keening? can you be keening? can he be keening? can we be keening? can you be keening? can they be keening?
Perfect
can I have keened? can you have keened? can he have keened? can we have keened? can you have keened? can they have keened?
V-ing perfect
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
can I not keen? can you not keen? can he not keen? can we not keen? can you not keen? can they not keen?
V-ing form
can I not be keening? can you not be keening? can he not be keening? can we not be keening? can you not be keening? can they not be keening?
Perfect
can I not have keened? can you not have keened? can he not have keened? can we not have keened? can you not have keened? can they not have keened?
V-ing perfect
can I not have been keening? can you not have been keening? can he not have been keening? can we not have been keening? can you not have been keening? can they not have been keening?