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