could knuckle
Verbo regular: knuckle - knuckled- knuckled

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could knuckle
you could knuckle
he could knuckle
we could knuckle
you could knuckle
they could knuckle 	I could be knuckling
you could be knuckling
he could be knuckling
we could be knuckling
you could be knuckling
they could be knuckling	I could have knuckled
you could have knuckled
he could have knuckled
we could have knuckled
you could have knuckled
they could have knuckled	I could have been knuckling
you could have been knuckling
he could have been knuckling
we could have been knuckling
you could have been knuckling
they could have been knuckling	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not knuckle
you could not knuckle
he could not knuckle
we could not knuckle
you could not knuckle
they could not knuckle 	I could not be knuckling
you could not be knuckling
he could not be knuckling
we could not be knuckling
you could not be knuckling
they could not be knuckling	I could not have knuckled
you could not have knuckled
he could not have knuckled
we could not have knuckled
you could not have knuckled
they could not have knuckled	I could not have been knuckling
you could not have been knuckling
he could not have been knuckling
we could not have been knuckling
you could not have been knuckling
they could not have been knuckling	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I knuckle?
could you knuckle?
could he knuckle?
could we knuckle?
could you knuckle?
could they knuckle? 	could I be knuckling?
could you be knuckling?
could he be knuckling?
could we be knuckling?
could you be knuckling?
could they be knuckling? 	could I have knuckled?
could you have knuckled?
could he have knuckled?
could we have knuckled?
could you have knuckled?
could they have knuckled? 	could I have been knuckling?
could you have been knuckling?
could he have been knuckling?
could we have been knuckling?
could you have been knuckling?
could they have been knuckling? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not knuckle?
could you not knuckle?
could he not knuckle?
could we not knuckle?
could you not knuckle?
could they not knuckle? 	could I not be knuckling?
could you not be knuckling?
could he not be knuckling?
could we not be knuckling?
could you not be knuckling?
could they not be knuckling? 	could I not have knuckled?
could you not have knuckled?
could he not have knuckled?
could we not have knuckled?
could you not have knuckled?
could they not have knuckled? 	could I not have been knuckling?
could you not have been knuckling?
could he not have been knuckling?
could we not have been knuckling?
could you not have been knuckling?
could they not have been knuckling?