could singe
Verbo regular: singe - singed- singed

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could singe
you could singe
she could singe
we could singe
you could singe
they could singe 	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 singed
you could have singed
she could have singed
we could have singed
you could have singed
they could have singed	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 couldn't singe
you couldn't singe
she couldn't singe
we couldn't singe
you couldn't singe
they couldn't singe 	I couldn't be singing
you couldn't be singing
she couldn't be singing
we couldn't be singing
you couldn't be singing
they couldn't be singing	I couldn't have singed
you couldn't have singed
she couldn't have singed
we couldn't have singed
you couldn't have singed
they couldn't have singed	I couldn't have been singing
you couldn't have been singing
she couldn't have been singing
we couldn't have been singing
you couldn't have been singing
they couldn't have been singing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I singe?
could you singe?
could she singe?
could we singe?
could you singe?
could they singe? 	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 singed?
could you have singed?
could she have singed?
could we have singed?
could you have singed?
could they have singed? 	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 	
couldn't I singe?
couldn't you singe?
couldn't she singe?
couldn't we singe?
couldn't you singe?
couldn't they singe? 	couldn't I be singing?
couldn't you be singing?
couldn't she be singing?
couldn't we be singing?
couldn't you be singing?
couldn't they be singing? 	couldn't I have singed?
couldn't you have singed?
couldn't she have singed?
couldn't we have singed?
couldn't you have singed?
couldn't they have singed? 	couldn't I have been singing?
couldn't you have been singing?
couldn't she have been singing?
couldn't we have been singing?
couldn't you have been singing?
couldn't they have been singing?