could smooth
Verbo regular: smooth - smoothed- smoothed

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could smooth
you could smooth
he could smooth
we could smooth
you could smooth
they could smooth 	I could be smoothing
you could be smoothing
he could be smoothing
we could be smoothing
you could be smoothing
they could be smoothing	I could have smoothed
you could have smoothed
he could have smoothed
we could have smoothed
you could have smoothed
they could have smoothed	I could have been smoothing
you could have been smoothing
he could have been smoothing
we could have been smoothing
you could have been smoothing
they could have been smoothing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not smooth
you could not smooth
he could not smooth
we could not smooth
you could not smooth
they could not smooth 	I could not be smoothing
you could not be smoothing
he could not be smoothing
we could not be smoothing
you could not be smoothing
they could not be smoothing	I could not have smoothed
you could not have smoothed
he could not have smoothed
we could not have smoothed
you could not have smoothed
they could not have smoothed	I could not have been smoothing
you could not have been smoothing
he could not have been smoothing
we could not have been smoothing
you could not have been smoothing
they could not have been smoothing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I smooth?
could you smooth?
could he smooth?
could we smooth?
could you smooth?
could they smooth? 	could I be smoothing?
could you be smoothing?
could he be smoothing?
could we be smoothing?
could you be smoothing?
could they be smoothing? 	could I have smoothed?
could you have smoothed?
could he have smoothed?
could we have smoothed?
could you have smoothed?
could they have smoothed? 	could I have been smoothing?
could you have been smoothing?
could he have been smoothing?
could we have been smoothing?
could you have been smoothing?
could they have been smoothing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not smooth?
could you not smooth?
could he not smooth?
could we not smooth?
could you not smooth?
could they not smooth? 	could I not be smoothing?
could you not be smoothing?
could he not be smoothing?
could we not be smoothing?
could you not be smoothing?
could they not be smoothing? 	could I not have smoothed?
could you not have smoothed?
could he not have smoothed?
could we not have smoothed?
could you not have smoothed?
could they not have smoothed? 	could I not have been smoothing?
could you not have been smoothing?
could he not have been smoothing?
could we not have been smoothing?
could you not have been smoothing?
could they not have been smoothing?