English verb conjugation
COULD RET

Regular verb: ret - retted - retted

Affirmation

Simple form	V-ing form
I could ret you could ret he could ret we could ret you could ret they could ret	I could be retting you could be retting he could be retting we could be retting you could be retting they could be retting
Perfect	V-ing perfect
I could have retted you could have retted he could have retted we could have retted you could have retted they could have retted	I could have been retting you could have been retting he could have been retting we could have been retting you could have been retting they could have been retting

Negation

Simple form	V-ing form
I couldn't ret you couldn't ret he couldn't ret we couldn't ret you couldn't ret they couldn't ret	I couldn't be retting you couldn't be retting he couldn't be retting we couldn't be retting you couldn't be retting they couldn't be retting
Perfect	V-ing perfect
I couldn't have retted you couldn't have retted he couldn't have retted we couldn't have retted you couldn't have retted they couldn't have retted	I couldn't have been retting you couldn't have been retting he couldn't have been retting we couldn't have been retting you couldn't have been retting they couldn't have been retting

Interrogative form

Simple form	V-ing form
could I ret? could you ret? could he ret? could we ret? could you ret? could they ret?	could I be retting? could you be retting? could he be retting? could we be retting? could you be retting? could they be retting?
Perfect	V-ing perfect
could I have retted? could you have retted? could he have retted? could we have retted? could you have retted? could they have retted?	could I have been retting? could you have been retting? could he have been retting? could we have been retting? could you have been retting? could they have been retting?

Interro-negative form

Simple form	V-ing form
couldn't I ret? couldn't you ret? couldn't he ret? couldn't we ret? couldn't you ret? couldn't they ret?	couldn't I be retting? couldn't you be retting? couldn't he be retting? couldn't we be retting? couldn't you be retting? couldn't they be retting?
Perfect	V-ing perfect
couldn't I have retted? couldn't you have retted? couldn't he have retted? couldn't we have retted? couldn't you have retted? couldn't they have retted?	couldn't I have been retting? couldn't you have been retting? couldn't he have been retting? couldn't we have been retting? couldn't you have been retting? couldn't they have been retting?