English verb conjugation
MUST EXIST

Regular verb: exist - existed - existed

Affirmation

Simple form	V-ing form
I must exist you must exist she must exist we must exist you must exist they must exist	I must be existing you must be existing she must be existing we must be existing you must be existing they must be existing
Perfect	V-ing perfect
I must have existed you must have existed she must have existed we must have existed you must have existed they must have existed	I must have been existing you must have been existing she must have been existing we must have been existing you must have been existing they must have been existing

Negation

Simple form	V-ing form
I mustn't exist you mustn't exist she mustn't exist we mustn't exist you mustn't exist they mustn't exist	I mustn't be existing you mustn't be existing she mustn't be existing we mustn't be existing you mustn't be existing they mustn't be existing
Perfect	V-ing perfect
I mustn't have existed you mustn't have existed she mustn't have existed we mustn't have existed you mustn't have existed they mustn't have existed	I mustn't have been existing you mustn't have been existing she mustn't have been existing we mustn't have been existing you mustn't have been existing they mustn't have been existing

Interrogative form

Simple form	V-ing form
must I exist? must you exist? must she exist? must we exist? must you exist? must they exist?	must I be existing? must you be existing? must she be existing? must we be existing? must you be existing? must they be existing?
Perfect	V-ing perfect
must I have existed? must you have existed? must she have existed? must we have existed? must you have existed? must they have existed?	must I have been existing? must you have been existing? must she have been existing? must we have been existing? must you have been existing? must they have been existing?

Interro-negative form

Simple form	V-ing form
mustn't I exist? mustn't you exist? mustn't she exist? mustn't we exist? mustn't you exist? mustn't they exist?	mustn't I be existing? mustn't you be existing? mustn't she be existing? mustn't we be existing? mustn't you be existing? mustn't they be existing?
Perfect	V-ing perfect
mustn't I have existed? mustn't you have existed? mustn't she have existed? mustn't we have existed? mustn't you have existed? mustn't they have existed?	mustn't I have been existing? mustn't you have been existing? mustn't she have been existing? mustn't we have been existing? mustn't you have been existing? mustn't they have been existing?