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