could perform
Verbo regular: perform - performed- performed

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could perform
you could perform
he could perform
we could perform
you could perform
they could perform 	I could be performing
you could be performing
he could be performing
we could be performing
you could be performing
they could be performing	I could have performed
you could have performed
he could have performed
we could have performed
you could have performed
they could have performed	I could have been performing
you could have been performing
he could have been performing
we could have been performing
you could have been performing
they could have been performing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't perform
you couldn't perform
he couldn't perform
we couldn't perform
you couldn't perform
they couldn't perform 	I couldn't be performing
you couldn't be performing
he couldn't be performing
we couldn't be performing
you couldn't be performing
they couldn't be performing	I couldn't have performed
you couldn't have performed
he couldn't have performed
we couldn't have performed
you couldn't have performed
they couldn't have performed	I couldn't have been performing
you couldn't have been performing
he couldn't have been performing
we couldn't have been performing
you couldn't have been performing
they couldn't have been performing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I perform?
could you perform?
could he perform?
could we perform?
could you perform?
could they perform? 	could I be performing?
could you be performing?
could he be performing?
could we be performing?
could you be performing?
could they be performing? 	could I have performed?
could you have performed?
could he have performed?
could we have performed?
could you have performed?
could they have performed? 	could I have been performing?
could you have been performing?
could he have been performing?
could we have been performing?
could you have been performing?
could they have been performing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I perform?
couldn't you perform?
couldn't he perform?
couldn't we perform?
couldn't you perform?
couldn't they perform? 	couldn't I be performing?
couldn't you be performing?
couldn't he be performing?
couldn't we be performing?
couldn't you be performing?
couldn't they be performing? 	couldn't I have performed?
couldn't you have performed?
couldn't he have performed?
couldn't we have performed?
couldn't you have performed?
couldn't they have performed? 	couldn't I have been performing?
couldn't you have been performing?
couldn't he have been performing?
couldn't we have been performing?
couldn't you have been performing?
couldn't they have been performing?