English verb conjugation
MUST LIGHTEN

Regular verb: lighten - lightened - lightened

Affirmation

Simple form	V-ing form
I must lighten you must lighten he must lighten we must lighten you must lighten they must lighten	I must be lightening you must be lightening he must be lightening we must be lightening you must be lightening they must be lightening
Perfect	V-ing perfect
I must have lightened you must have lightened he must have lightened we must have lightened you must have lightened they must have lightened	I must have been lightening you must have been lightening he must have been lightening we must have been lightening you must have been lightening they must have been lightening

Negation

Simple form	V-ing form
I mustn't lighten you mustn't lighten he mustn't lighten we mustn't lighten you mustn't lighten they mustn't lighten	I mustn't be lightening you mustn't be lightening he mustn't be lightening we mustn't be lightening you mustn't be lightening they mustn't be lightening
Perfect	V-ing perfect
I mustn't have lightened you mustn't have lightened he mustn't have lightened we mustn't have lightened you mustn't have lightened they mustn't have lightened	I mustn't have been lightening you mustn't have been lightening he mustn't have been lightening we mustn't have been lightening you mustn't have been lightening they mustn't have been lightening

Interrogative form

Simple form	V-ing form
must I lighten? must you lighten? must he lighten? must we lighten? must you lighten? must they lighten?	must I be lightening? must you be lightening? must he be lightening? must we be lightening? must you be lightening? must they be lightening?
Perfect	V-ing perfect
must I have lightened? must you have lightened? must he have lightened? must we have lightened? must you have lightened? must they have lightened?	must I have been lightening? must you have been lightening? must he have been lightening? must we have been lightening? must you have been lightening? must they have been lightening?

Interro-negative form

Simple form	V-ing form
mustn't I lighten? mustn't you lighten? mustn't he lighten? mustn't we lighten? mustn't you lighten? mustn't they lighten?	mustn't I be lightening? mustn't you be lightening? mustn't he be lightening? mustn't we be lightening? mustn't you be lightening? mustn't they be lightening?
Perfect	V-ing perfect
mustn't I have lightened? mustn't you have lightened? mustn't he have lightened? mustn't we have lightened? mustn't you have lightened? mustn't they have lightened?	mustn't I have been lightening? mustn't you have been lightening? mustn't he have been lightening? mustn't we have been lightening? mustn't you have been lightening? mustn't they have been lightening?