English verb conjugation
COULD ECHO

Regular verb: echo - echoed - echoed

Affirmation

Simple form	V-ing form
I could echo you could echo he could echo we could echo you could echo they could echo	I could be echoing you could be echoing he could be echoing we could be echoing you could be echoing they could be echoing
Perfect	V-ing perfect
I could have echoed you could have echoed he 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 he could have been echoing we could have been echoing you could have been echoing they could have been echoing

Negation

Simple form	V-ing form
I could not echo you could not echo he 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 he could not be echoing we could not be echoing you could not be echoing they could not be echoing
Perfect	V-ing perfect
I could not have echoed you could not have echoed he 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 he could not have been echoing we could not have been echoing you could not have been echoing they could not have been echoing

Interrogative form

Simple form	V-ing form
could I echo? could you echo? could he echo? could we echo? could you echo? could they echo?	could I be echoing? could you be echoing? could he be echoing? could we be echoing? could you be echoing? could they be echoing?
Perfect	V-ing perfect
could I have echoed? could you have echoed? could he 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 he have been echoing? could we have been echoing? could you have been echoing? could they have been echoing?

Interro-negative form

Simple form	V-ing form
could I not echo? could you not echo? could he 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 he not be echoing? could we not be echoing? could you not be echoing? could they not be echoing?
Perfect	V-ing perfect
could I not have echoed? could you not have echoed? could he 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 he not have been echoing? could we not have been echoing? could you not have been echoing? could they not have been echoing?