I must scare you must scare she must scare we must scare you must scare they must scare
V-ing form
I must be scaring you must be scaring she must be scaring we must be scaring you must be scaring they must be scaring
Perfect
I must have scared you must have scared she 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 she 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 she 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 she 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 she 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 she 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 she scare? must we scare? must you scare? must they scare?
V-ing form
must I be scaring? must you be scaring? must she be scaring? must we be scaring? must you be scaring? must they be scaring?
Perfect
must I have scared? must you have scared? must she 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 she 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 she 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 she 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 she 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 she have been scaring? mustn't we have been scaring? mustn't you have been scaring? mustn't they have been scaring?