could retain
Verbo regular: retain - retained- retained

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could retain
you could retain
he could retain
we could retain
you could retain
they could retain 	I could be retaining
you could be retaining
he could be retaining
we could be retaining
you could be retaining
they could be retaining	I could have retained
you could have retained
he could have retained
we could have retained
you could have retained
they could have retained	I could have been retaining
you could have been retaining
he could have been retaining
we could have been retaining
you could have been retaining
they could have been retaining	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't retain
you couldn't retain
he couldn't retain
we couldn't retain
you couldn't retain
they couldn't retain 	I couldn't be retaining
you couldn't be retaining
he couldn't be retaining
we couldn't be retaining
you couldn't be retaining
they couldn't be retaining	I couldn't have retained
you couldn't have retained
he couldn't have retained
we couldn't have retained
you couldn't have retained
they couldn't have retained	I couldn't have been retaining
you couldn't have been retaining
he couldn't have been retaining
we couldn't have been retaining
you couldn't have been retaining
they couldn't have been retaining	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I retain?
could you retain?
could he retain?
could we retain?
could you retain?
could they retain? 	could I be retaining?
could you be retaining?
could he be retaining?
could we be retaining?
could you be retaining?
could they be retaining? 	could I have retained?
could you have retained?
could he have retained?
could we have retained?
could you have retained?
could they have retained? 	could I have been retaining?
could you have been retaining?
could he have been retaining?
could we have been retaining?
could you have been retaining?
could they have been retaining? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I retain?
couldn't you retain?
couldn't he retain?
couldn't we retain?
couldn't you retain?
couldn't they retain? 	couldn't I be retaining?
couldn't you be retaining?
couldn't he be retaining?
couldn't we be retaining?
couldn't you be retaining?
couldn't they be retaining? 	couldn't I have retained?
couldn't you have retained?
couldn't he have retained?
couldn't we have retained?
couldn't you have retained?
couldn't they have retained? 	couldn't I have been retaining?
couldn't you have been retaining?
couldn't he have been retaining?
couldn't we have been retaining?
couldn't you have been retaining?
couldn't they have been retaining?