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