English verb conjugation
MUST SIT

Irregular verb: sit - sat - sat

Affirmation

Simple form	V-ing form
I must sit you must sit he must sit we must sit you must sit they must sit	I must be sitting you must be sitting he must be sitting we must be sitting you must be sitting they must be sitting
Perfect	V-ing perfect
I must have sat you must have sat he must have sat we must have sat you must have sat they must have sat	I must have been sitting you must have been sitting he must have been sitting we must have been sitting you must have been sitting they must have been sitting

Negation

Simple form	V-ing form
I mustn't sit you mustn't sit he mustn't sit we mustn't sit you mustn't sit they mustn't sit	I mustn't be sitting you mustn't be sitting he mustn't be sitting we mustn't be sitting you mustn't be sitting they mustn't be sitting
Perfect	V-ing perfect
I mustn't have sat you mustn't have sat he mustn't have sat we mustn't have sat you mustn't have sat they mustn't have sat	I mustn't have been sitting you mustn't have been sitting he mustn't have been sitting we mustn't have been sitting you mustn't have been sitting they mustn't have been sitting

Interrogative form

Simple form	V-ing form
must I sit? must you sit? must he sit? must we sit? must you sit? must they sit?	must I be sitting? must you be sitting? must he be sitting? must we be sitting? must you be sitting? must they be sitting?
Perfect	V-ing perfect
must I have sat? must you have sat? must he have sat? must we have sat? must you have sat? must they have sat?	must I have been sitting? must you have been sitting? must he have been sitting? must we have been sitting? must you have been sitting? must they have been sitting?

Interro-negative form

Simple form	V-ing form
mustn't I sit? mustn't you sit? mustn't he sit? mustn't we sit? mustn't you sit? mustn't they sit?	mustn't I be sitting? mustn't you be sitting? mustn't he be sitting? mustn't we be sitting? mustn't you be sitting? mustn't they be sitting?
Perfect	V-ing perfect
mustn't I have sat? mustn't you have sat? mustn't he have sat? mustn't we have sat? mustn't you have sat? mustn't they have sat?	mustn't I have been sitting? mustn't you have been sitting? mustn't he have been sitting? mustn't we have been sitting? mustn't you have been sitting? mustn't they have been sitting?