could refine
Verbo regular: refine - refined- refined

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could refine
you could refine
he could refine
we could refine
you could refine
they could refine 	I could be refining
you could be refining
he could be refining
we could be refining
you could be refining
they could be refining	I could have refined
you could have refined
he could have refined
we could have refined
you could have refined
they could have refined	I could have been refining
you could have been refining
he could have been refining
we could have been refining
you could have been refining
they could have been refining	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not refine
you could not refine
he could not refine
we could not refine
you could not refine
they could not refine 	I could not be refining
you could not be refining
he could not be refining
we could not be refining
you could not be refining
they could not be refining	I could not have refined
you could not have refined
he could not have refined
we could not have refined
you could not have refined
they could not have refined	I could not have been refining
you could not have been refining
he could not have been refining
we could not have been refining
you could not have been refining
they could not have been refining	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I refine?
could you refine?
could he refine?
could we refine?
could you refine?
could they refine? 	could I be refining?
could you be refining?
could he be refining?
could we be refining?
could you be refining?
could they be refining? 	could I have refined?
could you have refined?
could he have refined?
could we have refined?
could you have refined?
could they have refined? 	could I have been refining?
could you have been refining?
could he have been refining?
could we have been refining?
could you have been refining?
could they have been refining? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not refine?
could you not refine?
could he not refine?
could we not refine?
could you not refine?
could they not refine? 	could I not be refining?
could you not be refining?
could he not be refining?
could we not be refining?
could you not be refining?
could they not be refining? 	could I not have refined?
could you not have refined?
could he not have refined?
could we not have refined?
could you not have refined?
could they not have refined? 	could I not have been refining?
could you not have been refining?
could he not have been refining?
could we not have been refining?
could you not have been refining?
could they not have been refining?