could filter
Verbo regular: filter - filtered- filtered

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could filter
you could filter
she could filter
we could filter
you could filter
they could filter 	I could be filtering
you could be filtering
she could be filtering
we could be filtering
you could be filtering
they could be filtering	I could have filtered
you could have filtered
she could have filtered
we could have filtered
you could have filtered
they could have filtered	I could have been filtering
you could have been filtering
she could have been filtering
we could have been filtering
you could have been filtering
they could have been filtering	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not filter
you could not filter
she could not filter
we could not filter
you could not filter
they could not filter 	I could not be filtering
you could not be filtering
she could not be filtering
we could not be filtering
you could not be filtering
they could not be filtering	I could not have filtered
you could not have filtered
she could not have filtered
we could not have filtered
you could not have filtered
they could not have filtered	I could not have been filtering
you could not have been filtering
she could not have been filtering
we could not have been filtering
you could not have been filtering
they could not have been filtering	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I filter?
could you filter?
could she filter?
could we filter?
could you filter?
could they filter? 	could I be filtering?
could you be filtering?
could she be filtering?
could we be filtering?
could you be filtering?
could they be filtering? 	could I have filtered?
could you have filtered?
could she have filtered?
could we have filtered?
could you have filtered?
could they have filtered? 	could I have been filtering?
could you have been filtering?
could she have been filtering?
could we have been filtering?
could you have been filtering?
could they have been filtering? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not filter?
could you not filter?
could she not filter?
could we not filter?
could you not filter?
could they not filter? 	could I not be filtering?
could you not be filtering?
could she not be filtering?
could we not be filtering?
could you not be filtering?
could they not be filtering? 	could I not have filtered?
could you not have filtered?
could she not have filtered?
could we not have filtered?
could you not have filtered?
could they not have filtered? 	could I not have been filtering?
could you not have been filtering?
could she not have been filtering?
could we not have been filtering?
could you not have been filtering?
could they not have been filtering?