could persevere
Regular verb: persevere - persevered- persevered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could persevere
you could persevere
she could persevere
we could persevere
you could persevere
they could persevere 	I could be persevering
you could be persevering
she could be persevering
we could be persevering
you could be persevering
they could be persevering	I could have persevered
you could have persevered
she could have persevered
we could have persevered
you could have persevered
they could have persevered	I could have been persevering
you could have been persevering
she could have been persevering
we could have been persevering
you could have been persevering
they could have been persevering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not persevere
you could not persevere
she could not persevere
we could not persevere
you could not persevere
they could not persevere 	I could not be persevering
you could not be persevering
she could not be persevering
we could not be persevering
you could not be persevering
they could not be persevering	I could not have persevered
you could not have persevered
she could not have persevered
we could not have persevered
you could not have persevered
they could not have persevered	I could not have been persevering
you could not have been persevering
she could not have been persevering
we could not have been persevering
you could not have been persevering
they could not have been persevering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I persevere?
could you persevere?
could she persevere?
could we persevere?
could you persevere?
could they persevere? 	could I be persevering?
could you be persevering?
could she be persevering?
could we be persevering?
could you be persevering?
could they be persevering? 	could I have persevered?
could you have persevered?
could she have persevered?
could we have persevered?
could you have persevered?
could they have persevered? 	could I have been persevering?
could you have been persevering?
could she have been persevering?
could we have been persevering?
could you have been persevering?
could they have been persevering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not persevere?
could you not persevere?
could she not persevere?
could we not persevere?
could you not persevere?
could they not persevere? 	could I not be persevering?
could you not be persevering?
could she not be persevering?
could we not be persevering?
could you not be persevering?
could they not be persevering? 	could I not have persevered?
could you not have persevered?
could she not have persevered?
could we not have persevered?
could you not have persevered?
could they not have persevered? 	could I not have been persevering?
could you not have been persevering?
could she not have been persevering?
could we not have been persevering?
could you not have been persevering?
could they not have been persevering?