could know
Verbo irregular: know - knew- known

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could know
you could know
she could know
we could know
you could know
they could know 	I could be knowing
you could be knowing
she could be knowing
we could be knowing
you could be knowing
they could be knowing	I could have known
you could have known
she could have known
we could have known
you could have known
they could have known	I could have been knowing
you could have been knowing
she could have been knowing
we could have been knowing
you could have been knowing
they could have been knowing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not know
you could not know
she could not know
we could not know
you could not know
they could not know 	I could not be knowing
you could not be knowing
she could not be knowing
we could not be knowing
you could not be knowing
they could not be knowing	I could not have known
you could not have known
she could not have known
we could not have known
you could not have known
they could not have known	I could not have been knowing
you could not have been knowing
she could not have been knowing
we could not have been knowing
you could not have been knowing
they could not have been knowing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I know?
could you know?
could she know?
could we know?
could you know?
could they know? 	could I be knowing?
could you be knowing?
could she be knowing?
could we be knowing?
could you be knowing?
could they be knowing? 	could I have known?
could you have known?
could she have known?
could we have known?
could you have known?
could they have known? 	could I have been knowing?
could you have been knowing?
could she have been knowing?
could we have been knowing?
could you have been knowing?
could they have been knowing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not know?
could you not know?
could she not know?
could we not know?
could you not know?
could they not know? 	could I not be knowing?
could you not be knowing?
could she not be knowing?
could we not be knowing?
could you not be knowing?
could they not be knowing? 	could I not have known?
could you not have known?
could she not have known?
could we not have known?
could you not have known?
could they not have known? 	could I not have been knowing?
could you not have been knowing?
could she not have been knowing?
could we not have been knowing?
could you not have been knowing?
could they not have been knowing?