could surface
Verbo regular: surface - surfaced- surfaced

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could surface
you could surface
she could surface
we could surface
you could surface
they could surface 	I could be surfacing
you could be surfacing
she could be surfacing
we could be surfacing
you could be surfacing
they could be surfacing	I could have surfaced
you could have surfaced
she could have surfaced
we could have surfaced
you could have surfaced
they could have surfaced	I could have been surfacing
you could have been surfacing
she could have been surfacing
we could have been surfacing
you could have been surfacing
they could have been surfacing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not surface
you could not surface
she could not surface
we could not surface
you could not surface
they could not surface 	I could not be surfacing
you could not be surfacing
she could not be surfacing
we could not be surfacing
you could not be surfacing
they could not be surfacing	I could not have surfaced
you could not have surfaced
she could not have surfaced
we could not have surfaced
you could not have surfaced
they could not have surfaced	I could not have been surfacing
you could not have been surfacing
she could not have been surfacing
we could not have been surfacing
you could not have been surfacing
they could not have been surfacing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I surface?
could you surface?
could she surface?
could we surface?
could you surface?
could they surface? 	could I be surfacing?
could you be surfacing?
could she be surfacing?
could we be surfacing?
could you be surfacing?
could they be surfacing? 	could I have surfaced?
could you have surfaced?
could she have surfaced?
could we have surfaced?
could you have surfaced?
could they have surfaced? 	could I have been surfacing?
could you have been surfacing?
could she have been surfacing?
could we have been surfacing?
could you have been surfacing?
could they have been surfacing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not surface?
could you not surface?
could she not surface?
could we not surface?
could you not surface?
could they not surface? 	could I not be surfacing?
could you not be surfacing?
could she not be surfacing?
could we not be surfacing?
could you not be surfacing?
could they not be surfacing? 	could I not have surfaced?
could you not have surfaced?
could she not have surfaced?
could we not have surfaced?
could you not have surfaced?
could they not have surfaced? 	could I not have been surfacing?
could you not have been surfacing?
could she not have been surfacing?
could we not have been surfacing?
could you not have been surfacing?
could they not have been surfacing?