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