English verb conjugation
MUST REGRESS

Regular verb: regress - regressed - regressed

Affirmation

Simple form	V-ing form
I must regress you must regress he must regress we must regress you must regress they must regress	I must be regressing you must be regressing he must be regressing we must be regressing you must be regressing they must be regressing
Perfect	V-ing perfect
I must have regressed you must have regressed he must have regressed we must have regressed you must have regressed they must have regressed	I must have been regressing you must have been regressing he must have been regressing we must have been regressing you must have been regressing they must have been regressing

Negation

Simple form	V-ing form
I mustn't regress you mustn't regress he mustn't regress we mustn't regress you mustn't regress they mustn't regress	I mustn't be regressing you mustn't be regressing he mustn't be regressing we mustn't be regressing you mustn't be regressing they mustn't be regressing
Perfect	V-ing perfect
I mustn't have regressed you mustn't have regressed he mustn't have regressed we mustn't have regressed you mustn't have regressed they mustn't have regressed	I mustn't have been regressing you mustn't have been regressing he mustn't have been regressing we mustn't have been regressing you mustn't have been regressing they mustn't have been regressing

Interrogative form

Simple form	V-ing form
must I regress? must you regress? must he regress? must we regress? must you regress? must they regress?	must I be regressing? must you be regressing? must he be regressing? must we be regressing? must you be regressing? must they be regressing?
Perfect	V-ing perfect
must I have regressed? must you have regressed? must he have regressed? must we have regressed? must you have regressed? must they have regressed?	must I have been regressing? must you have been regressing? must he have been regressing? must we have been regressing? must you have been regressing? must they have been regressing?

Interro-negative form

Simple form	V-ing form
mustn't I regress? mustn't you regress? mustn't he regress? mustn't we regress? mustn't you regress? mustn't they regress?	mustn't I be regressing? mustn't you be regressing? mustn't he be regressing? mustn't we be regressing? mustn't you be regressing? mustn't they be regressing?
Perfect	V-ing perfect
mustn't I have regressed? mustn't you have regressed? mustn't he have regressed? mustn't we have regressed? mustn't you have regressed? mustn't they have regressed?	mustn't I have been regressing? mustn't you have been regressing? mustn't he have been regressing? mustn't we have been regressing? mustn't you have been regressing? mustn't they have been regressing?