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