English verb conjugation
MUST SIGH

Regular verb: sigh - sighed - sighed

Affirmation

Simple form	V-ing form
I must sigh you must sigh he must sigh we must sigh you must sigh they must sigh	I must be sighing you must be sighing he must be sighing we must be sighing you must be sighing they must be sighing
Perfect	V-ing perfect
I must have sighed you must have sighed he must have sighed we must have sighed you must have sighed they must have sighed	I must have been sighing you must have been sighing he must have been sighing we must have been sighing you must have been sighing they must have been sighing

Negation

Simple form	V-ing form
I mustn't sigh you mustn't sigh he mustn't sigh we mustn't sigh you mustn't sigh they mustn't sigh	I mustn't be sighing you mustn't be sighing he mustn't be sighing we mustn't be sighing you mustn't be sighing they mustn't be sighing
Perfect	V-ing perfect
I mustn't have sighed you mustn't have sighed he mustn't have sighed we mustn't have sighed you mustn't have sighed they mustn't have sighed	I mustn't have been sighing you mustn't have been sighing he mustn't have been sighing we mustn't have been sighing you mustn't have been sighing they mustn't have been sighing

Interrogative form

Simple form	V-ing form
must I sigh? must you sigh? must he sigh? must we sigh? must you sigh? must they sigh?	must I be sighing? must you be sighing? must he be sighing? must we be sighing? must you be sighing? must they be sighing?
Perfect	V-ing perfect
must I have sighed? must you have sighed? must he have sighed? must we have sighed? must you have sighed? must they have sighed?	must I have been sighing? must you have been sighing? must he have been sighing? must we have been sighing? must you have been sighing? must they have been sighing?

Interro-negative form

Simple form	V-ing form
mustn't I sigh? mustn't you sigh? mustn't he sigh? mustn't we sigh? mustn't you sigh? mustn't they sigh?	mustn't I be sighing? mustn't you be sighing? mustn't he be sighing? mustn't we be sighing? mustn't you be sighing? mustn't they be sighing?
Perfect	V-ing perfect
mustn't I have sighed? mustn't you have sighed? mustn't he have sighed? mustn't we have sighed? mustn't you have sighed? mustn't they have sighed?	mustn't I have been sighing? mustn't you have been sighing? mustn't he have been sighing? mustn't we have been sighing? mustn't you have been sighing? mustn't they have been sighing?