could fester
Verbo regular: fester - festered- festered

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could fester
you could fester
she could fester
we could fester
you could fester
they could fester 	I could be festering
you could be festering
she could be festering
we could be festering
you could be festering
they could be festering	I could have festered
you could have festered
she 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
she could have been festering
we could have been festering
you could have been festering
they could have been festering	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't fester
you couldn't fester
she 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
she couldn't be festering
we couldn't be festering
you couldn't be festering
they couldn't be festering	I couldn't have festered
you couldn't have festered
she 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
she couldn't have been festering
we couldn't have been festering
you couldn't have been festering
they couldn't have been festering	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I fester?
could you fester?
could she fester?
could we fester?
could you fester?
could they fester? 	could I be festering?
could you be festering?
could she be festering?
could we be festering?
could you be festering?
could they be festering? 	could I have festered?
could you have festered?
could she 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 she have been festering?
could we have been festering?
could you have been festering?
could they have been festering? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I fester?
couldn't you fester?
couldn't she 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 she be festering?
couldn't we be festering?
couldn't you be festering?
couldn't they be festering? 	couldn't I have festered?
couldn't you have festered?
couldn't she 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 she have been festering?
couldn't we have been festering?
couldn't you have been festering?
couldn't they have been festering?