I must lesson you must lesson she must lesson we must lesson you must lesson they must lesson
V-ing form
I must be lessoning you must be lessoning she must be lessoning we must be lessoning you must be lessoning they must be lessoning
Perfect
I must have lessoned you must have lessoned she must have lessoned we must have lessoned you must have lessoned they must have lessoned
V-ing perfect
I must have been lessoning you must have been lessoning she must have been lessoning we must have been lessoning you must have been lessoning they must have been lessoning
Negation
Simple form
I must not lesson you must not lesson she must not lesson we must not lesson you must not lesson they must not lesson
V-ing form
I must not be lessoning you must not be lessoning she must not be lessoning we must not be lessoning you must not be lessoning they must not be lessoning
Perfect
I must not have lessoned you must not have lessoned she must not have lessoned we must not have lessoned you must not have lessoned they must not have lessoned
V-ing perfect
I must not have been lessoning you must not have been lessoning she must not have been lessoning we must not have been lessoning you must not have been lessoning they must not have been lessoning
Interrogative form
Simple form
must I lesson? must you lesson? must she lesson? must we lesson? must you lesson? must they lesson?
V-ing form
must I be lessoning? must you be lessoning? must she be lessoning? must we be lessoning? must you be lessoning? must they be lessoning?
Perfect
must I have lessoned? must you have lessoned? must she have lessoned? must we have lessoned? must you have lessoned? must they have lessoned?
V-ing perfect
must I have been lessoning? must you have been lessoning? must she have been lessoning? must we have been lessoning? must you have been lessoning? must they have been lessoning?
Interro-negative form
Simple form
must I not lesson? must you not lesson? must she not lesson? must we not lesson? must you not lesson? must they not lesson?
V-ing form
must I not be lessoning? must you not be lessoning? must she not be lessoning? must we not be lessoning? must you not be lessoning? must they not be lessoning?
Perfect
must I not have lessoned? must you not have lessoned? must she not have lessoned? must we not have lessoned? must you not have lessoned? must they not have lessoned?
V-ing perfect
must I not have been lessoning? must you not have been lessoning? must she not have been lessoning? must we not have been lessoning? must you not have been lessoning? must they not have been lessoning?