I must liven you must liven she must liven we must liven you must liven they must liven
V-ing form
I must be livening you must be livening she must be livening we must be livening you must be livening they must be livening
Perfect
I must have livened you must have livened she must have livened we must have livened you must have livened they must have livened
V-ing perfect
I must have been livening you must have been livening she must have been livening we must have been livening you must have been livening they must have been livening
Negation
Simple form
I must not liven you must not liven she must not liven we must not liven you must not liven they must not liven
V-ing form
I must not be livening you must not be livening she must not be livening we must not be livening you must not be livening they must not be livening
Perfect
I must not have livened you must not have livened she must not have livened we must not have livened you must not have livened they must not have livened
V-ing perfect
I must not have been livening you must not have been livening she must not have been livening we must not have been livening you must not have been livening they must not have been livening
Interrogative form
Simple form
must I liven? must you liven? must she liven? must we liven? must you liven? must they liven?
V-ing form
must I be livening? must you be livening? must she be livening? must we be livening? must you be livening? must they be livening?
Perfect
must I have livened? must you have livened? must she have livened? must we have livened? must you have livened? must they have livened?
V-ing perfect
must I have been livening? must you have been livening? must she have been livening? must we have been livening? must you have been livening? must they have been livening?
Interro-negative form
Simple form
must I not liven? must you not liven? must she not liven? must we not liven? must you not liven? must they not liven?
V-ing form
must I not be livening? must you not be livening? must she not be livening? must we not be livening? must you not be livening? must they not be livening?
Perfect
must I not have livened? must you not have livened? must she not have livened? must we not have livened? must you not have livened? must they not have livened?
V-ing perfect
must I not have been livening? must you not have been livening? must she not have been livening? must we not have been livening? must you not have been livening? must they not have been livening?