could fester
Verbo regular: fester - festered- festered

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
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	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	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not fester
you could not fester
he could not fester
we could not fester
you could not fester
they could not fester 	I could not be festering
you could not be festering
he could not be festering
we could not be festering
you could not be festering
they could not be festering	I could not have festered
you could not have festered
he could not have festered
we could not have festered
you could not have festered
they could not have festered	I could not have been festering
you could not have been festering
he could not have been festering
we could not have been festering
you could not have been festering
they could not have been festering	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
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? 	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? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not fester?
could you not fester?
could he not fester?
could we not fester?
could you not fester?
could they not fester? 	could I not be festering?
could you not be festering?
could he not be festering?
could we not be festering?
could you not be festering?
could they not be festering? 	could I not have festered?
could you not have festered?
could he not have festered?
could we not have festered?
could you not have festered?
could they not have festered? 	could I not have been festering?
could you not have been festering?
could he not have been festering?
could we not have been festering?
could you not have been festering?
could they not have been festering?