English verb conjugation
MUST FROWN

Regular verb: frown - frowned - frowned

Affirmation

Simple form	V-ing form
I must frown you must frown he must frown we must frown you must frown they must frown	I must be frowning you must be frowning he must be frowning we must be frowning you must be frowning they must be frowning
Perfect	V-ing perfect
I must have frowned you must have frowned he must have frowned we must have frowned you must have frowned they must have frowned	I must have been frowning you must have been frowning he must have been frowning we must have been frowning you must have been frowning they must have been frowning

Negation

Simple form	V-ing form
I mustn't frown you mustn't frown he mustn't frown we mustn't frown you mustn't frown they mustn't frown	I mustn't be frowning you mustn't be frowning he mustn't be frowning we mustn't be frowning you mustn't be frowning they mustn't be frowning
Perfect	V-ing perfect
I mustn't have frowned you mustn't have frowned he mustn't have frowned we mustn't have frowned you mustn't have frowned they mustn't have frowned	I mustn't have been frowning you mustn't have been frowning he mustn't have been frowning we mustn't have been frowning you mustn't have been frowning they mustn't have been frowning

Interrogative form

Simple form	V-ing form
must I frown? must you frown? must he frown? must we frown? must you frown? must they frown?	must I be frowning? must you be frowning? must he be frowning? must we be frowning? must you be frowning? must they be frowning?
Perfect	V-ing perfect
must I have frowned? must you have frowned? must he have frowned? must we have frowned? must you have frowned? must they have frowned?	must I have been frowning? must you have been frowning? must he have been frowning? must we have been frowning? must you have been frowning? must they have been frowning?

Interro-negative form

Simple form	V-ing form
mustn't I frown? mustn't you frown? mustn't he frown? mustn't we frown? mustn't you frown? mustn't they frown?	mustn't I be frowning? mustn't you be frowning? mustn't he be frowning? mustn't we be frowning? mustn't you be frowning? mustn't they be frowning?
Perfect	V-ing perfect
mustn't I have frowned? mustn't you have frowned? mustn't he have frowned? mustn't we have frowned? mustn't you have frowned? mustn't they have frowned?	mustn't I have been frowning? mustn't you have been frowning? mustn't he have been frowning? mustn't we have been frowning? mustn't you have been frowning? mustn't they have been frowning?