English verb conjugation
COULD FESTER

Regular verb: fester - festered - festered

Affirmation

Simple form	V-ing form
I could fester you could fester he could fester we could fester you could fester they could fester	I could be festering you could be festering he could be festering we could be festering you could be festering they could be festering
Perfect	V-ing perfect
I could have festered you could have festered he could have festered we could have festered you could have festered they could have festered	I could have been festering you could have been festering he could have been festering we could have been festering you could have been festering they could have been festering

Negation

Simple form	V-ing form
I couldn't fester you couldn't fester he couldn't fester we couldn't fester you couldn't fester they couldn't fester	I couldn't be festering you couldn't be festering he couldn't be festering we couldn't be festering you couldn't be festering they couldn't be festering
Perfect	V-ing perfect
I couldn't have festered you couldn't have festered he couldn't have festered we couldn't have festered you couldn't have festered they couldn't have festered	I couldn't have been festering you couldn't have been festering he couldn't have been festering we couldn't have been festering you couldn't have been festering they couldn't have been festering

Interrogative form

Simple form	V-ing form
could I fester? could you fester? could he fester? could we fester? could you fester? could they fester?	could I be festering? could you be festering? could he be festering? could we be festering? could you be festering? could they be festering?
Perfect	V-ing perfect
could I have festered? could you have festered? could he have festered? could we have festered? could you have festered? could they have festered?	could I have been festering? could you have been festering? could he have been festering? could we have been festering? could you have been festering? could they have been festering?

Interro-negative form

Simple form	V-ing form
couldn't I fester? couldn't you fester? couldn't he fester? couldn't we fester? couldn't you fester? couldn't they fester?	couldn't I be festering? couldn't you be festering? couldn't he be festering? couldn't we be festering? couldn't you be festering? couldn't they be festering?
Perfect	V-ing perfect
couldn't I have festered? couldn't you have festered? couldn't he have festered? couldn't we have festered? couldn't you have festered? couldn't they have festered?	couldn't I have been festering? couldn't you have been festering? couldn't he have been festering? couldn't we have been festering? couldn't you have been festering? couldn't they have been festering?