English verb conjugation
MUST KNOW

Irregular verb: know - knew - known

Affirmation

Simple form	V-ing form
I must know you must know he must know we must know you must know they must know	I must be knowing you must be knowing he must be knowing we must be knowing you must be knowing they must be knowing
Perfect	V-ing perfect
I must have known you must have known he must have known we must have known you must have known they must have known	I must have been knowing you must have been knowing he must have been knowing we must have been knowing you must have been knowing they must have been knowing

Negation

Simple form	V-ing form
I mustn't know you mustn't know he mustn't know we mustn't know you mustn't know they mustn't know	I mustn't be knowing you mustn't be knowing he mustn't be knowing we mustn't be knowing you mustn't be knowing they mustn't be knowing
Perfect	V-ing perfect
I mustn't have known you mustn't have known he mustn't have known we mustn't have known you mustn't have known they mustn't have known	I mustn't have been knowing you mustn't have been knowing he mustn't have been knowing we mustn't have been knowing you mustn't have been knowing they mustn't have been knowing

Interrogative form

Simple form	V-ing form
must I know? must you know? must he know? must we know? must you know? must they know?	must I be knowing? must you be knowing? must he be knowing? must we be knowing? must you be knowing? must they be knowing?
Perfect	V-ing perfect
must I have known? must you have known? must he have known? must we have known? must you have known? must they have known?	must I have been knowing? must you have been knowing? must he have been knowing? must we have been knowing? must you have been knowing? must they have been knowing?

Interro-negative form

Simple form	V-ing form
mustn't I know? mustn't you know? mustn't he know? mustn't we know? mustn't you know? mustn't they know?	mustn't I be knowing? mustn't you be knowing? mustn't he be knowing? mustn't we be knowing? mustn't you be knowing? mustn't they be knowing?
Perfect	V-ing perfect
mustn't I have known? mustn't you have known? mustn't he have known? mustn't we have known? mustn't you have known? mustn't they have known?	mustn't I have been knowing? mustn't you have been knowing? mustn't he have been knowing? mustn't we have been knowing? mustn't you have been knowing? mustn't they have been knowing?