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 must not retrogress you must not retrogress he must not retrogress we must not retrogress you must not retrogress they must not retrogress	I must not be retrogressing you must not be retrogressing he must not be retrogressing we must not be retrogressing you must not be retrogressing they must not be retrogressing
Perfect	V-ing perfect
I must not have retrogressed you must not have retrogressed he must not have retrogressed we must not have retrogressed you must not have retrogressed they must not have retrogressed	I must not have been retrogressing you must not have been retrogressing he must not have been retrogressing we must not have been retrogressing you must not have been retrogressing they must not 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
must I not retrogress? must you not retrogress? must he not retrogress? must we not retrogress? must you not retrogress? must they not retrogress?	must I not be retrogressing? must you not be retrogressing? must he not be retrogressing? must we not be retrogressing? must you not be retrogressing? must they not be retrogressing?
Perfect	V-ing perfect
must I not have retrogressed? must you not have retrogressed? must he not have retrogressed? must we not have retrogressed? must you not have retrogressed? must they not have retrogressed?	must I not have been retrogressing? must you not have been retrogressing? must he not have been retrogressing? must we not have been retrogressing? must you not have been retrogressing? must they not have been retrogressing?