I must stare you must stare he must stare we must stare you must stare they must stare
V-ing form
I must be staring you must be staring he must be staring we must be staring you must be staring they must be staring
Perfect
I must have stared you must have stared he must have stared we must have stared you must have stared they must have stared
V-ing perfect
I must have been staring you must have been staring he must have been staring we must have been staring you must have been staring they must have been staring
Negation
Simple form
I must not stare you must not stare he must not stare we must not stare you must not stare they must not stare
V-ing form
I must not be staring you must not be staring he must not be staring we must not be staring you must not be staring they must not be staring
Perfect
I must not have stared you must not have stared he must not have stared we must not have stared you must not have stared they must not have stared
V-ing perfect
I must not have been staring you must not have been staring he must not have been staring we must not have been staring you must not have been staring they must not have been staring
Interrogative form
Simple form
must I stare? must you stare? must he stare? must we stare? must you stare? must they stare?
V-ing form
must I be staring? must you be staring? must he be staring? must we be staring? must you be staring? must they be staring?
Perfect
must I have stared? must you have stared? must he have stared? must we have stared? must you have stared? must they have stared?
V-ing perfect
must I have been staring? must you have been staring? must he have been staring? must we have been staring? must you have been staring? must they have been staring?
Interro-negative form
Simple form
must I not stare? must you not stare? must he not stare? must we not stare? must you not stare? must they not stare?
V-ing form
must I not be staring? must you not be staring? must he not be staring? must we not be staring? must you not be staring? must they not be staring?
Perfect
must I not have stared? must you not have stared? must he not have stared? must we not have stared? must you not have stared? must they not have stared?
V-ing perfect
must I not have been staring? must you not have been staring? must he not have been staring? must we not have been staring? must you not have been staring? must they not have been staring?