I must bork you must bork she must bork we must bork you must bork they must bork
V-ing form
I must be borking you must be borking she must be borking we must be borking you must be borking they must be borking
Perfect
I must have borked you must have borked she 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 she must have been borking we must have been borking you must have been borking they must have been borking
Negation
Simple form
I must not bork you must not bork she must not bork we must not bork you must not bork they must not bork
V-ing form
I must not be borking you must not be borking she must not be borking we must not be borking you must not be borking they must not be borking
Perfect
I must not have borked you must not have borked she must not have borked we must not have borked you must not have borked they must not have borked
V-ing perfect
I must not have been borking you must not have been borking she must not have been borking we must not have been borking you must not have been borking they must not have been borking
Interrogative form
Simple form
must I bork? must you bork? must she bork? must we bork? must you bork? must they bork?
V-ing form
must I be borking? must you be borking? must she be borking? must we be borking? must you be borking? must they be borking?
Perfect
must I have borked? must you have borked? must she 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 she have been borking? must we have been borking? must you have been borking? must they have been borking?
Interro-negative form
Simple form
must I not bork? must you not bork? must she not bork? must we not bork? must you not bork? must they not bork?
V-ing form
must I not be borking? must you not be borking? must she not be borking? must we not be borking? must you not be borking? must they not be borking?
Perfect
must I not have borked? must you not have borked? must she not have borked? must we not have borked? must you not have borked? must they not have borked?
V-ing perfect
must I not have been borking? must you not have been borking? must she not have been borking? must we not have been borking? must you not have been borking? must they not have been borking?