could fever
Regular verb: fever - fevered- fevered

Affirmation 	
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I could fever
you could fever
she could fever
we could fever
you could fever
they could fever 	I could be fevering
you could be fevering
she could be fevering
we could be fevering
you could be fevering
they could be fevering	I could have fevered
you could have fevered
she could have fevered
we could have fevered
you could have fevered
they could have fevered	I could have been fevering
you could have been fevering
she could have been fevering
we could have been fevering
you could have been fevering
they could have been fevering	

Negation 	
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I could not fever
you could not fever
she could not fever
we could not fever
you could not fever
they could not fever 	I could not be fevering
you could not be fevering
she could not be fevering
we could not be fevering
you could not be fevering
they could not be fevering	I could not have fevered
you could not have fevered
she could not have fevered
we could not have fevered
you could not have fevered
they could not have fevered	I could not have been fevering
you could not have been fevering
she could not have been fevering
we could not have been fevering
you could not have been fevering
they could not have been fevering	

Interrogative form 	
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could I fever?
could you fever?
could she fever?
could we fever?
could you fever?
could they fever? 	could I be fevering?
could you be fevering?
could she be fevering?
could we be fevering?
could you be fevering?
could they be fevering? 	could I have fevered?
could you have fevered?
could she have fevered?
could we have fevered?
could you have fevered?
could they have fevered? 	could I have been fevering?
could you have been fevering?
could she have been fevering?
could we have been fevering?
could you have been fevering?
could they have been fevering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not fever?
could you not fever?
could she not fever?
could we not fever?
could you not fever?
could they not fever? 	could I not be fevering?
could you not be fevering?
could she not be fevering?
could we not be fevering?
could you not be fevering?
could they not be fevering? 	could I not have fevered?
could you not have fevered?
could she not have fevered?
could we not have fevered?
could you not have fevered?
could they not have fevered? 	could I not have been fevering?
could you not have been fevering?
could she not have been fevering?
could we not have been fevering?
could you not have been fevering?
could they not have been fevering?