can fester
Regular verb: fester - festered- festered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can fester
you can fester
she can fester
we can fester
you can fester
they can fester 	I can be festering
you can be festering
she can be festering
we can be festering
you can be festering
they can be festering	I can have festered
you can have festered
she can have festered
we can have festered
you can have festered
they can have festered	I can have been festering
you can have been festering
she can have been festering
we can have been festering
you can have been festering
they can have been festering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot fester
you cannot fester
she cannot fester
we cannot fester
you cannot fester
they cannot fester 	I cannot be festering
you cannot be festering
she cannot be festering
we cannot be festering
you cannot be festering
they cannot be festering	I cannot have festered
you cannot have festered
she cannot have festered
we cannot have festered
you cannot have festered
they cannot have festered	I cannot have been festering
you cannot have been festering
she cannot have been festering
we cannot have been festering
you cannot have been festering
they cannot have been festering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I fester?
can you fester?
can she fester?
can we fester?
can you fester?
can they fester? 	can I be festering?
can you be festering?
can she be festering?
can we be festering?
can you be festering?
can they be festering? 	can I have festered?
can you have festered?
can she have festered?
can we have festered?
can you have festered?
can they have festered? 	can I have been festering?
can you have been festering?
can she have been festering?
can we have been festering?
can you have been festering?
can they have been festering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not fester?
can you not fester?
can she not fester?
can we not fester?
can you not fester?
can they not fester? 	can I not be festering?
can you not be festering?
can she not be festering?
can we not be festering?
can you not be festering?
can they not be festering? 	can I not have festered?
can you not have festered?
can she not have festered?
can we not have festered?
can you not have festered?
can they not have festered? 	can I not have been festering?
can you not have been festering?
can she not have been festering?
can we not have been festering?
can you not have been festering?
can they not have been festering?