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 mustn't stare you mustn't stare he mustn't stare we mustn't stare you mustn't stare they mustn't stare
V-ing form
I mustn't be staring you mustn't be staring he mustn't be staring we mustn't be staring you mustn't be staring they mustn't be staring
Perfect
I mustn't have stared you mustn't have stared he mustn't have stared we mustn't have stared you mustn't have stared they mustn't have stared
V-ing perfect
I mustn't have been staring you mustn't have been staring he mustn't have been staring we mustn't have been staring you mustn't have been staring they mustn't 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
mustn't I stare? mustn't you stare? mustn't he stare? mustn't we stare? mustn't you stare? mustn't they stare?
V-ing form
mustn't I be staring? mustn't you be staring? mustn't he be staring? mustn't we be staring? mustn't you be staring? mustn't they be staring?
Perfect
mustn't I have stared? mustn't you have stared? mustn't he have stared? mustn't we have stared? mustn't you have stared? mustn't they have stared?
V-ing perfect
mustn't I have been staring? mustn't you have been staring? mustn't he have been staring? mustn't we have been staring? mustn't you have been staring? mustn't they have been staring?