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