I must oblige you must oblige he must oblige we must oblige you must oblige they must oblige
V-ing form
I must be obliging you must be obliging he must be obliging we must be obliging you must be obliging they must be obliging
Perfect
I must have obliged you must have obliged he must have obliged we must have obliged you must have obliged they must have obliged
V-ing perfect
I must have been obliging you must have been obliging he must have been obliging we must have been obliging you must have been obliging they must have been obliging
Negation
Simple form
I mustn't oblige you mustn't oblige he mustn't oblige we mustn't oblige you mustn't oblige they mustn't oblige
V-ing form
I mustn't be obliging you mustn't be obliging he mustn't be obliging we mustn't be obliging you mustn't be obliging they mustn't be obliging
Perfect
I mustn't have obliged you mustn't have obliged he mustn't have obliged we mustn't have obliged you mustn't have obliged they mustn't have obliged
V-ing perfect
I mustn't have been obliging you mustn't have been obliging he mustn't have been obliging we mustn't have been obliging you mustn't have been obliging they mustn't have been obliging
Interrogative form
Simple form
must I oblige? must you oblige? must he oblige? must we oblige? must you oblige? must they oblige?
V-ing form
must I be obliging? must you be obliging? must he be obliging? must we be obliging? must you be obliging? must they be obliging?
Perfect
must I have obliged? must you have obliged? must he have obliged? must we have obliged? must you have obliged? must they have obliged?
V-ing perfect
must I have been obliging? must you have been obliging? must he have been obliging? must we have been obliging? must you have been obliging? must they have been obliging?
Interro-negative form
Simple form
mustn't I oblige? mustn't you oblige? mustn't he oblige? mustn't we oblige? mustn't you oblige? mustn't they oblige?
V-ing form
mustn't I be obliging? mustn't you be obliging? mustn't he be obliging? mustn't we be obliging? mustn't you be obliging? mustn't they be obliging?
Perfect
mustn't I have obliged? mustn't you have obliged? mustn't he have obliged? mustn't we have obliged? mustn't you have obliged? mustn't they have obliged?
V-ing perfect
mustn't I have been obliging? mustn't you have been obliging? mustn't he have been obliging? mustn't we have been obliging? mustn't you have been obliging? mustn't they have been obliging?