English verb conjugation
COULD FRET

Regular verb: fret - fretted - fretted

Affirmation

Simple form	V-ing form
I could fret you could fret he could fret we could fret you could fret they could fret	I could be fretting you could be fretting he could be fretting we could be fretting you could be fretting they could be fretting
Perfect	V-ing perfect
I could have fretted you could have fretted he could have fretted we could have fretted you could have fretted they could have fretted	I could have been fretting you could have been fretting he could have been fretting we could have been fretting you could have been fretting they could have been fretting

Negation

Simple form	V-ing form
I couldn't fret you couldn't fret he couldn't fret we couldn't fret you couldn't fret they couldn't fret	I couldn't be fretting you couldn't be fretting he couldn't be fretting we couldn't be fretting you couldn't be fretting they couldn't be fretting
Perfect	V-ing perfect
I couldn't have fretted you couldn't have fretted he couldn't have fretted we couldn't have fretted you couldn't have fretted they couldn't have fretted	I couldn't have been fretting you couldn't have been fretting he couldn't have been fretting we couldn't have been fretting you couldn't have been fretting they couldn't have been fretting

Interrogative form

Simple form	V-ing form
could I fret? could you fret? could he fret? could we fret? could you fret? could they fret?	could I be fretting? could you be fretting? could he be fretting? could we be fretting? could you be fretting? could they be fretting?
Perfect	V-ing perfect
could I have fretted? could you have fretted? could he have fretted? could we have fretted? could you have fretted? could they have fretted?	could I have been fretting? could you have been fretting? could he have been fretting? could we have been fretting? could you have been fretting? could they have been fretting?

Interro-negative form

Simple form	V-ing form
couldn't I fret? couldn't you fret? couldn't he fret? couldn't we fret? couldn't you fret? couldn't they fret?	couldn't I be fretting? couldn't you be fretting? couldn't he be fretting? couldn't we be fretting? couldn't you be fretting? couldn't they be fretting?
Perfect	V-ing perfect
couldn't I have fretted? couldn't you have fretted? couldn't he have fretted? couldn't we have fretted? couldn't you have fretted? couldn't they have fretted?	couldn't I have been fretting? couldn't you have been fretting? couldn't he have been fretting? couldn't we have been fretting? couldn't you have been fretting? couldn't they have been fretting?