English verb conjugation
MUST KEEN

Regular verb: keen - keened - keened

Affirmation

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

Negation

Simple form	V-ing form
I must not keen you must not keen he must not keen we must not keen you must not keen they must not keen	I must not be keening you must not be keening he must not be keening we must not be keening you must not be keening they must not be keening
Perfect	V-ing perfect
I must not have keened you must not have keened he must not have keened we must not have keened you must not have keened they must not have keened	I must not have been keening you must not have been keening he must not have been keening we must not have been keening you must not have been keening they must not have been keening

Interrogative form

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

Interro-negative form

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