I must change you must change he must change we must change you must change they must change
V-ing form
I must be changing you must be changing he must be changing we must be changing you must be changing they must be changing
Perfect
I must have changed you must have changed he must have changed we must have changed you must have changed they must have changed
V-ing perfect
I must have been changing you must have been changing he must have been changing we must have been changing you must have been changing they must have been changing
Negation
Simple form
I must not change you must not change he must not change we must not change you must not change they must not change
V-ing form
I must not be changing you must not be changing he must not be changing we must not be changing you must not be changing they must not be changing
Perfect
I must not have changed you must not have changed he must not have changed we must not have changed you must not have changed they must not have changed
V-ing perfect
I must not have been changing you must not have been changing he must not have been changing we must not have been changing you must not have been changing they must not have been changing
Interrogative form
Simple form
must I change? must you change? must he change? must we change? must you change? must they change?
V-ing form
must I be changing? must you be changing? must he be changing? must we be changing? must you be changing? must they be changing?
Perfect
must I have changed? must you have changed? must he have changed? must we have changed? must you have changed? must they have changed?
V-ing perfect
must I have been changing? must you have been changing? must he have been changing? must we have been changing? must you have been changing? must they have been changing?
Interro-negative form
Simple form
must I not change? must you not change? must he not change? must we not change? must you not change? must they not change?
V-ing form
must I not be changing? must you not be changing? must he not be changing? must we not be changing? must you not be changing? must they not be changing?
Perfect
must I not have changed? must you not have changed? must he not have changed? must we not have changed? must you not have changed? must they not have changed?
V-ing perfect
must I not have been changing? must you not have been changing? must he not have been changing? must we not have been changing? must you not have been changing? must they not have been changing?