could echo
Verbo regular: echo - echoed- echoed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could echo
you could echo
she could echo
we could echo
you could echo
they could echo 	I could be echoing
you could be echoing
she could be echoing
we could be echoing
you could be echoing
they could be echoing	I could have echoed
you could have echoed
she could have echoed
we could have echoed
you could have echoed
they could have echoed	I could have been echoing
you could have been echoing
she could have been echoing
we could have been echoing
you could have been echoing
they could have been echoing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could not echo
you could not echo
she could not echo
we could not echo
you could not echo
they could not echo 	I could not be echoing
you could not be echoing
she could not be echoing
we could not be echoing
you could not be echoing
they could not be echoing	I could not have echoed
you could not have echoed
she could not have echoed
we could not have echoed
you could not have echoed
they could not have echoed	I could not have been echoing
you could not have been echoing
she could not have been echoing
we could not have been echoing
you could not have been echoing
they could not have been echoing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I echo?
could you echo?
could she echo?
could we echo?
could you echo?
could they echo? 	could I be echoing?
could you be echoing?
could she be echoing?
could we be echoing?
could you be echoing?
could they be echoing? 	could I have echoed?
could you have echoed?
could she have echoed?
could we have echoed?
could you have echoed?
could they have echoed? 	could I have been echoing?
could you have been echoing?
could she have been echoing?
could we have been echoing?
could you have been echoing?
could they have been echoing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I not echo?
could you not echo?
could she not echo?
could we not echo?
could you not echo?
could they not echo? 	could I not be echoing?
could you not be echoing?
could she not be echoing?
could we not be echoing?
could you not be echoing?
could they not be echoing? 	could I not have echoed?
could you not have echoed?
could she not have echoed?
could we not have echoed?
could you not have echoed?
could they not have echoed? 	could I not have been echoing?
could you not have been echoing?
could she not have been echoing?
could we not have been echoing?
could you not have been echoing?
could they not have been echoing?