I must ache you must ache he must ache we must ache you must ache they must ache
V-ing form
I must be aching you must be aching he must be aching we must be aching you must be aching they must be aching
Perfect
I must have ached you must have ached he must have ached we must have ached you must have ached they must have ached
V-ing perfect
I must have been aching you must have been aching he must have been aching we must have been aching you must have been aching they must have been aching
Negation
Simple form
I must not ache you must not ache he must not ache we must not ache you must not ache they must not ache
V-ing form
I must not be aching you must not be aching he must not be aching we must not be aching you must not be aching they must not be aching
Perfect
I must not have ached you must not have ached he must not have ached we must not have ached you must not have ached they must not have ached
V-ing perfect
I must not have been aching you must not have been aching he must not have been aching we must not have been aching you must not have been aching they must not have been aching
Interrogative form
Simple form
must I ache? must you ache? must he ache? must we ache? must you ache? must they ache?
V-ing form
must I be aching? must you be aching? must he be aching? must we be aching? must you be aching? must they be aching?
Perfect
must I have ached? must you have ached? must he have ached? must we have ached? must you have ached? must they have ached?
V-ing perfect
must I have been aching? must you have been aching? must he have been aching? must we have been aching? must you have been aching? must they have been aching?
Interro-negative form
Simple form
must I not ache? must you not ache? must he not ache? must we not ache? must you not ache? must they not ache?
V-ing form
must I not be aching? must you not be aching? must he not be aching? must we not be aching? must you not be aching? must they not be aching?
Perfect
must I not have ached? must you not have ached? must he not have ached? must we not have ached? must you not have ached? must they not have ached?
V-ing perfect
must I not have been aching? must you not have been aching? must he not have been aching? must we not have been aching? must you not have been aching? must they not have been aching?