could ref
Verbo regular: ref - refed- refed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could ref
you could ref
he could ref
we could ref
you could ref
they could ref 	I could be refing
you could be refing
he could be refing
we could be refing
you could be refing
they could be refing	I could have refed
you could have refed
he could have refed
we could have refed
you could have refed
they could have refed	I could have been refing
you could have been refing
he could have been refing
we could have been refing
you could have been refing
they could have been refing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't ref
you couldn't ref
he couldn't ref
we couldn't ref
you couldn't ref
they couldn't ref 	I couldn't be refing
you couldn't be refing
he couldn't be refing
we couldn't be refing
you couldn't be refing
they couldn't be refing	I couldn't have refed
you couldn't have refed
he couldn't have refed
we couldn't have refed
you couldn't have refed
they couldn't have refed	I couldn't have been refing
you couldn't have been refing
he couldn't have been refing
we couldn't have been refing
you couldn't have been refing
they couldn't have been refing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I ref?
could you ref?
could he ref?
could we ref?
could you ref?
could they ref? 	could I be refing?
could you be refing?
could he be refing?
could we be refing?
could you be refing?
could they be refing? 	could I have refed?
could you have refed?
could he have refed?
could we have refed?
could you have refed?
could they have refed? 	could I have been refing?
could you have been refing?
could he have been refing?
could we have been refing?
could you have been refing?
could they have been refing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I ref?
couldn't you ref?
couldn't he ref?
couldn't we ref?
couldn't you ref?
couldn't they ref? 	couldn't I be refing?
couldn't you be refing?
couldn't he be refing?
couldn't we be refing?
couldn't you be refing?
couldn't they be refing? 	couldn't I have refed?
couldn't you have refed?
couldn't he have refed?
couldn't we have refed?
couldn't you have refed?
couldn't they have refed? 	couldn't I have been refing?
couldn't you have been refing?
couldn't he have been refing?
couldn't we have been refing?
couldn't you have been refing?
couldn't they have been refing?