could curtain
Verbo regular: curtain - curtained- curtained

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could curtain
you could curtain
he could curtain
we could curtain
you could curtain
they could curtain 	I could be curtaining
you could be curtaining
he could be curtaining
we could be curtaining
you could be curtaining
they could be curtaining	I could have curtained
you could have curtained
he could have curtained
we could have curtained
you could have curtained
they could have curtained	I could have been curtaining
you could have been curtaining
he could have been curtaining
we could have been curtaining
you could have been curtaining
they could have been curtaining	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could not curtain
you could not curtain
he could not curtain
we could not curtain
you could not curtain
they could not curtain 	I could not be curtaining
you could not be curtaining
he could not be curtaining
we could not be curtaining
you could not be curtaining
they could not be curtaining	I could not have curtained
you could not have curtained
he could not have curtained
we could not have curtained
you could not have curtained
they could not have curtained	I could not have been curtaining
you could not have been curtaining
he could not have been curtaining
we could not have been curtaining
you could not have been curtaining
they could not have been curtaining	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I curtain?
could you curtain?
could he curtain?
could we curtain?
could you curtain?
could they curtain? 	could I be curtaining?
could you be curtaining?
could he be curtaining?
could we be curtaining?
could you be curtaining?
could they be curtaining? 	could I have curtained?
could you have curtained?
could he have curtained?
could we have curtained?
could you have curtained?
could they have curtained? 	could I have been curtaining?
could you have been curtaining?
could he have been curtaining?
could we have been curtaining?
could you have been curtaining?
could they have been curtaining? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I not curtain?
could you not curtain?
could he not curtain?
could we not curtain?
could you not curtain?
could they not curtain? 	could I not be curtaining?
could you not be curtaining?
could he not be curtaining?
could we not be curtaining?
could you not be curtaining?
could they not be curtaining? 	could I not have curtained?
could you not have curtained?
could he not have curtained?
could we not have curtained?
could you not have curtained?
could they not have curtained? 	could I not have been curtaining?
could you not have been curtaining?
could he not have been curtaining?
could we not have been curtaining?
could you not have been curtaining?
could they not have been curtaining?