English verb conjugation
MUST RETROGRESS

Regular verb: retrogress - retrogressed - retrogressed

Affirmation

Simple form	V-ing form
I must retrogress you must retrogress he must retrogress we must retrogress you must retrogress they must retrogress	I must be retrogressing you must be retrogressing he must be retrogressing we must be retrogressing you must be retrogressing they must be retrogressing
Perfect	V-ing perfect
I must have retrogressed you must have retrogressed he must have retrogressed we must have retrogressed you must have retrogressed they must have retrogressed	I must have been retrogressing you must have been retrogressing he must have been retrogressing we must have been retrogressing you must have been retrogressing they must have been retrogressing

Negation

Simple form	V-ing form
I mustn't retrogress you mustn't retrogress he mustn't retrogress we mustn't retrogress you mustn't retrogress they mustn't retrogress	I mustn't be retrogressing you mustn't be retrogressing he mustn't be retrogressing we mustn't be retrogressing you mustn't be retrogressing they mustn't be retrogressing
Perfect	V-ing perfect
I mustn't have retrogressed you mustn't have retrogressed he mustn't have retrogressed we mustn't have retrogressed you mustn't have retrogressed they mustn't have retrogressed	I mustn't have been retrogressing you mustn't have been retrogressing he mustn't have been retrogressing we mustn't have been retrogressing you mustn't have been retrogressing they mustn't have been retrogressing

Interrogative form

Simple form	V-ing form
must I retrogress? must you retrogress? must he retrogress? must we retrogress? must you retrogress? must they retrogress?	must I be retrogressing? must you be retrogressing? must he be retrogressing? must we be retrogressing? must you be retrogressing? must they be retrogressing?
Perfect	V-ing perfect
must I have retrogressed? must you have retrogressed? must he have retrogressed? must we have retrogressed? must you have retrogressed? must they have retrogressed?	must I have been retrogressing? must you have been retrogressing? must he have been retrogressing? must we have been retrogressing? must you have been retrogressing? must they have been retrogressing?

Interro-negative form

Simple form	V-ing form
mustn't I retrogress? mustn't you retrogress? mustn't he retrogress? mustn't we retrogress? mustn't you retrogress? mustn't they retrogress?	mustn't I be retrogressing? mustn't you be retrogressing? mustn't he be retrogressing? mustn't we be retrogressing? mustn't you be retrogressing? mustn't they be retrogressing?
Perfect	V-ing perfect
mustn't I have retrogressed? mustn't you have retrogressed? mustn't he have retrogressed? mustn't we have retrogressed? mustn't you have retrogressed? mustn't they have retrogressed?	mustn't I have been retrogressing? mustn't you have been retrogressing? mustn't he have been retrogressing? mustn't we have been retrogressing? mustn't you have been retrogressing? mustn't they have been retrogressing?