I must mix you must mix he must mix we must mix you must mix they must mix
V-ing form
I must be mixing you must be mixing he must be mixing we must be mixing you must be mixing they must be mixing
Perfect
I must have mixed you must have mixed he must have mixed we must have mixed you must have mixed they must have mixed
V-ing perfect
I must have been mixing you must have been mixing he must have been mixing we must have been mixing you must have been mixing they must have been mixing
Negation
Simple form
I must not mix you must not mix he must not mix we must not mix you must not mix they must not mix
V-ing form
I must not be mixing you must not be mixing he must not be mixing we must not be mixing you must not be mixing they must not be mixing
Perfect
I must not have mixed you must not have mixed he must not have mixed we must not have mixed you must not have mixed they must not have mixed
V-ing perfect
I must not have been mixing you must not have been mixing he must not have been mixing we must not have been mixing you must not have been mixing they must not have been mixing
Interrogative form
Simple form
must I mix? must you mix? must he mix? must we mix? must you mix? must they mix?
V-ing form
must I be mixing? must you be mixing? must he be mixing? must we be mixing? must you be mixing? must they be mixing?
Perfect
must I have mixed? must you have mixed? must he have mixed? must we have mixed? must you have mixed? must they have mixed?
V-ing perfect
must I have been mixing? must you have been mixing? must he have been mixing? must we have been mixing? must you have been mixing? must they have been mixing?
Interro-negative form
Simple form
must I not mix? must you not mix? must he not mix? must we not mix? must you not mix? must they not mix?
V-ing form
must I not be mixing? must you not be mixing? must he not be mixing? must we not be mixing? must you not be mixing? must they not be mixing?
Perfect
must I not have mixed? must you not have mixed? must he not have mixed? must we not have mixed? must you not have mixed? must they not have mixed?
V-ing perfect
must I not have been mixing? must you not have been mixing? must he not have been mixing? must we not have been mixing? must you not have been mixing? must they not have been mixing?