English verb conjugation
MUST REGRESS

Regular verb: regress - regressed - regressed

Affirmation

Simple form	V-ing form
I must regress you must regress she must regress we must regress you must regress they must regress	I must be regressing you must be regressing she 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 she 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 she 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 she 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 she 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 she 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 she 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 she regress? must we regress? must you regress? must they regress?	must I be regressing? must you be regressing? must she 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 she 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 she 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 she 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 she 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 she 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 she have been regressing? mustn't we have been regressing? mustn't you have been regressing? mustn't they have been regressing?