English verb conjugation
COULD YAP

Regular verb: yap - yapped - yapped

Affirmation

Simple form	V-ing form
I could yap you could yap he could yap we could yap you could yap they could yap	I could be yapping you could be yapping he could be yapping we could be yapping you could be yapping they could be yapping
Perfect	V-ing perfect
I could have yapped you could have yapped he could have yapped we could have yapped you could have yapped they could have yapped	I could have been yapping you could have been yapping he could have been yapping we could have been yapping you could have been yapping they could have been yapping

Negation

Simple form	V-ing form
I could not yap you could not yap he could not yap we could not yap you could not yap they could not yap	I could not be yapping you could not be yapping he could not be yapping we could not be yapping you could not be yapping they could not be yapping
Perfect	V-ing perfect
I could not have yapped you could not have yapped he could not have yapped we could not have yapped you could not have yapped they could not have yapped	I could not have been yapping you could not have been yapping he could not have been yapping we could not have been yapping you could not have been yapping they could not have been yapping

Interrogative form

Simple form	V-ing form
could I yap? could you yap? could he yap? could we yap? could you yap? could they yap?	could I be yapping? could you be yapping? could he be yapping? could we be yapping? could you be yapping? could they be yapping?
Perfect	V-ing perfect
could I have yapped? could you have yapped? could he have yapped? could we have yapped? could you have yapped? could they have yapped?	could I have been yapping? could you have been yapping? could he have been yapping? could we have been yapping? could you have been yapping? could they have been yapping?

Interro-negative form

Simple form	V-ing form
could I not yap? could you not yap? could he not yap? could we not yap? could you not yap? could they not yap?	could I not be yapping? could you not be yapping? could he not be yapping? could we not be yapping? could you not be yapping? could they not be yapping?
Perfect	V-ing perfect
could I not have yapped? could you not have yapped? could he not have yapped? could we not have yapped? could you not have yapped? could they not have yapped?	could I not have been yapping? could you not have been yapping? could he not have been yapping? could we not have been yapping? could you not have been yapping? could they not have been yapping?