could biff
Verbo regular: biff - biffed- biffed

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could biff
you could biff
she could biff
we could biff
you could biff
they could biff 	I could be biffing
you could be biffing
she could be biffing
we could be biffing
you could be biffing
they could be biffing	I could have biffed
you could have biffed
she could have biffed
we could have biffed
you could have biffed
they could have biffed	I could have been biffing
you could have been biffing
she could have been biffing
we could have been biffing
you could have been biffing
they could have been biffing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not biff
you could not biff
she could not biff
we could not biff
you could not biff
they could not biff 	I could not be biffing
you could not be biffing
she could not be biffing
we could not be biffing
you could not be biffing
they could not be biffing	I could not have biffed
you could not have biffed
she could not have biffed
we could not have biffed
you could not have biffed
they could not have biffed	I could not have been biffing
you could not have been biffing
she could not have been biffing
we could not have been biffing
you could not have been biffing
they could not have been biffing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I biff?
could you biff?
could she biff?
could we biff?
could you biff?
could they biff? 	could I be biffing?
could you be biffing?
could she be biffing?
could we be biffing?
could you be biffing?
could they be biffing? 	could I have biffed?
could you have biffed?
could she have biffed?
could we have biffed?
could you have biffed?
could they have biffed? 	could I have been biffing?
could you have been biffing?
could she have been biffing?
could we have been biffing?
could you have been biffing?
could they have been biffing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not biff?
could you not biff?
could she not biff?
could we not biff?
could you not biff?
could they not biff? 	could I not be biffing?
could you not be biffing?
could she not be biffing?
could we not be biffing?
could you not be biffing?
could they not be biffing? 	could I not have biffed?
could you not have biffed?
could she not have biffed?
could we not have biffed?
could you not have biffed?
could they not have biffed? 	could I not have been biffing?
could you not have been biffing?
could she not have been biffing?
could we not have been biffing?
could you not have been biffing?
could they not have been biffing?