could nibble
Verbo regular: nibble - nibbled- nibbled

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could nibble
you could nibble
he could nibble
we could nibble
you could nibble
they could nibble 	I could be nibbling
you could be nibbling
he could be nibbling
we could be nibbling
you could be nibbling
they could be nibbling	I could have nibbled
you could have nibbled
he could have nibbled
we could have nibbled
you could have nibbled
they could have nibbled	I could have been nibbling
you could have been nibbling
he could have been nibbling
we could have been nibbling
you could have been nibbling
they could have been nibbling	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not nibble
you could not nibble
he could not nibble
we could not nibble
you could not nibble
they could not nibble 	I could not be nibbling
you could not be nibbling
he could not be nibbling
we could not be nibbling
you could not be nibbling
they could not be nibbling	I could not have nibbled
you could not have nibbled
he could not have nibbled
we could not have nibbled
you could not have nibbled
they could not have nibbled	I could not have been nibbling
you could not have been nibbling
he could not have been nibbling
we could not have been nibbling
you could not have been nibbling
they could not have been nibbling	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I nibble?
could you nibble?
could he nibble?
could we nibble?
could you nibble?
could they nibble? 	could I be nibbling?
could you be nibbling?
could he be nibbling?
could we be nibbling?
could you be nibbling?
could they be nibbling? 	could I have nibbled?
could you have nibbled?
could he have nibbled?
could we have nibbled?
could you have nibbled?
could they have nibbled? 	could I have been nibbling?
could you have been nibbling?
could he have been nibbling?
could we have been nibbling?
could you have been nibbling?
could they have been nibbling? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not nibble?
could you not nibble?
could he not nibble?
could we not nibble?
could you not nibble?
could they not nibble? 	could I not be nibbling?
could you not be nibbling?
could he not be nibbling?
could we not be nibbling?
could you not be nibbling?
could they not be nibbling? 	could I not have nibbled?
could you not have nibbled?
could he not have nibbled?
could we not have nibbled?
could you not have nibbled?
could they not have nibbled? 	could I not have been nibbling?
could you not have been nibbling?
could he not have been nibbling?
could we not have been nibbling?
could you not have been nibbling?
could they not have been nibbling?