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