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