I must act you must act she must act we must act you must act they must act
V-ing form
I must be acting you must be acting she must be acting we must be acting you must be acting they must be acting
Perfect
I must have acted you must have acted she must have acted we must have acted you must have acted they must have acted
V-ing perfect
I must have been acting you must have been acting she must have been acting we must have been acting you must have been acting they must have been acting
Negation
Simple form
I must not act you must not act she must not act we must not act you must not act they must not act
V-ing form
I must not be acting you must not be acting she must not be acting we must not be acting you must not be acting they must not be acting
Perfect
I must not have acted you must not have acted she must not have acted we must not have acted you must not have acted they must not have acted
V-ing perfect
I must not have been acting you must not have been acting she must not have been acting we must not have been acting you must not have been acting they must not have been acting
Interrogative form
Simple form
must I act? must you act? must she act? must we act? must you act? must they act?
V-ing form
must I be acting? must you be acting? must she be acting? must we be acting? must you be acting? must they be acting?
Perfect
must I have acted? must you have acted? must she have acted? must we have acted? must you have acted? must they have acted?
V-ing perfect
must I have been acting? must you have been acting? must she have been acting? must we have been acting? must you have been acting? must they have been acting?
Interro-negative form
Simple form
must I not act? must you not act? must she not act? must we not act? must you not act? must they not act?
V-ing form
must I not be acting? must you not be acting? must she not be acting? must we not be acting? must you not be acting? must they not be acting?
Perfect
must I not have acted? must you not have acted? must she not have acted? must we not have acted? must you not have acted? must they not have acted?
V-ing perfect
must I not have been acting? must you not have been acting? must she not have been acting? must we not have been acting? must you not have been acting? must they not have been acting?