could sing
Verbo irregular: sing - sang- sung

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could sing
you could sing
she could sing
we could sing
you could sing
they could sing 	I could be singing
you could be singing
she could be singing
we could be singing
you could be singing
they could be singing	I could have sung
you could have sung
she could have sung
we could have sung
you could have sung
they could have sung	I could have been singing
you could have been singing
she could have been singing
we could have been singing
you could have been singing
they could have been singing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not sing
you could not sing
she could not sing
we could not sing
you could not sing
they could not sing 	I could not be singing
you could not be singing
she could not be singing
we could not be singing
you could not be singing
they could not be singing	I could not have sung
you could not have sung
she could not have sung
we could not have sung
you could not have sung
they could not have sung	I could not have been singing
you could not have been singing
she could not have been singing
we could not have been singing
you could not have been singing
they could not have been singing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I sing?
could you sing?
could she sing?
could we sing?
could you sing?
could they sing? 	could I be singing?
could you be singing?
could she be singing?
could we be singing?
could you be singing?
could they be singing? 	could I have sung?
could you have sung?
could she have sung?
could we have sung?
could you have sung?
could they have sung? 	could I have been singing?
could you have been singing?
could she have been singing?
could we have been singing?
could you have been singing?
could they have been singing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not sing?
could you not sing?
could she not sing?
could we not sing?
could you not sing?
could they not sing? 	could I not be singing?
could you not be singing?
could she not be singing?
could we not be singing?
could you not be singing?
could they not be singing? 	could I not have sung?
could you not have sung?
could she not have sung?
could we not have sung?
could you not have sung?
could they not have sung? 	could I not have been singing?
could you not have been singing?
could she not have been singing?
could we not have been singing?
could you not have been singing?
could they not have been singing?