could change
Verbo regular: change - changed- changed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could change
you could change
he could change
we could change
you could change
they could change 	I could be changing
you could be changing
he could be changing
we could be changing
you could be changing
they could be changing	I could have changed
you could have changed
he could have changed
we could have changed
you could have changed
they could have changed	I could have been changing
you could have been changing
he could have been changing
we could have been changing
you could have been changing
they could have been changing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could not change
you could not change
he could not change
we could not change
you could not change
they could not change 	I could not be changing
you could not be changing
he could not be changing
we could not be changing
you could not be changing
they could not be changing	I could not have changed
you could not have changed
he could not have changed
we could not have changed
you could not have changed
they could not have changed	I could not have been changing
you could not have been changing
he could not have been changing
we could not have been changing
you could not have been changing
they could not have been changing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I change?
could you change?
could he change?
could we change?
could you change?
could they change? 	could I be changing?
could you be changing?
could he be changing?
could we be changing?
could you be changing?
could they be changing? 	could I have changed?
could you have changed?
could he have changed?
could we have changed?
could you have changed?
could they have changed? 	could I have been changing?
could you have been changing?
could he have been changing?
could we have been changing?
could you have been changing?
could they have been changing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I not change?
could you not change?
could he not change?
could we not change?
could you not change?
could they not change? 	could I not be changing?
could you not be changing?
could he not be changing?
could we not be changing?
could you not be changing?
could they not be changing? 	could I not have changed?
could you not have changed?
could he not have changed?
could we not have changed?
could you not have changed?
could they not have changed? 	could I not have been changing?
could you not have been changing?
could he not have been changing?
could we not have been changing?
could you not have been changing?
could they not have been changing?