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