I must ask you must ask she must ask we must ask you must ask they must ask
V-ing form
I must be asking you must be asking she must be asking we must be asking you must be asking they must be asking
Perfect
I must have asked you must have asked she must have asked we must have asked you must have asked they must have asked
V-ing perfect
I must have been asking you must have been asking she must have been asking we must have been asking you must have been asking they must have been asking
Negation
Simple form
I mustn't ask you mustn't ask she mustn't ask we mustn't ask you mustn't ask they mustn't ask
V-ing form
I mustn't be asking you mustn't be asking she mustn't be asking we mustn't be asking you mustn't be asking they mustn't be asking
Perfect
I mustn't have asked you mustn't have asked she mustn't have asked we mustn't have asked you mustn't have asked they mustn't have asked
V-ing perfect
I mustn't have been asking you mustn't have been asking she mustn't have been asking we mustn't have been asking you mustn't have been asking they mustn't have been asking
Interrogative form
Simple form
must I ask? must you ask? must she ask? must we ask? must you ask? must they ask?
V-ing form
must I be asking? must you be asking? must she be asking? must we be asking? must you be asking? must they be asking?
Perfect
must I have asked? must you have asked? must she have asked? must we have asked? must you have asked? must they have asked?
V-ing perfect
must I have been asking? must you have been asking? must she have been asking? must we have been asking? must you have been asking? must they have been asking?
Interro-negative form
Simple form
mustn't I ask? mustn't you ask? mustn't she ask? mustn't we ask? mustn't you ask? mustn't they ask?
V-ing form
mustn't I be asking? mustn't you be asking? mustn't she be asking? mustn't we be asking? mustn't you be asking? mustn't they be asking?
Perfect
mustn't I have asked? mustn't you have asked? mustn't she have asked? mustn't we have asked? mustn't you have asked? mustn't they have asked?
V-ing perfect
mustn't I have been asking? mustn't you have been asking? mustn't she have been asking? mustn't we have been asking? mustn't you have been asking? mustn't they have been asking?