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