English verb conjugation
COULD RETROGRESS

Regular verb: retrogress - retrogressed - retrogressed

Affirmation

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

Negation

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

Interrogative form

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

Interro-negative form

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