I must fortify you must fortify she must fortify we must fortify you must fortify they must fortify
V-ing form
I must be fortifying you must be fortifying she must be fortifying we must be fortifying you must be fortifying they must be fortifying
Perfect
I must have fortified you must have fortified she must have fortified we must have fortified you must have fortified they must have fortified
V-ing perfect
I must have been fortifying you must have been fortifying she must have been fortifying we must have been fortifying you must have been fortifying they must have been fortifying
Negation
Simple form
I must not fortify you must not fortify she must not fortify we must not fortify you must not fortify they must not fortify
V-ing form
I must not be fortifying you must not be fortifying she must not be fortifying we must not be fortifying you must not be fortifying they must not be fortifying
Perfect
I must not have fortified you must not have fortified she must not have fortified we must not have fortified you must not have fortified they must not have fortified
V-ing perfect
I must not have been fortifying you must not have been fortifying she must not have been fortifying we must not have been fortifying you must not have been fortifying they must not have been fortifying
Interrogative form
Simple form
must I fortify? must you fortify? must she fortify? must we fortify? must you fortify? must they fortify?
V-ing form
must I be fortifying? must you be fortifying? must she be fortifying? must we be fortifying? must you be fortifying? must they be fortifying?
Perfect
must I have fortified? must you have fortified? must she have fortified? must we have fortified? must you have fortified? must they have fortified?
V-ing perfect
must I have been fortifying? must you have been fortifying? must she have been fortifying? must we have been fortifying? must you have been fortifying? must they have been fortifying?
Interro-negative form
Simple form
must I not fortify? must you not fortify? must she not fortify? must we not fortify? must you not fortify? must they not fortify?
V-ing form
must I not be fortifying? must you not be fortifying? must she not be fortifying? must we not be fortifying? must you not be fortifying? must they not be fortifying?
Perfect
must I not have fortified? must you not have fortified? must she not have fortified? must we not have fortified? must you not have fortified? must they not have fortified?
V-ing perfect
must I not have been fortifying? must you not have been fortifying? must she not have been fortifying? must we not have been fortifying? must you not have been fortifying? must they not have been fortifying?