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 couldn't yap you couldn't yap he couldn't yap we couldn't yap you couldn't yap they couldn't yap	I couldn't be yapping you couldn't be yapping he couldn't be yapping we couldn't be yapping you couldn't be yapping they couldn't be yapping
Perfect	V-ing perfect
I couldn't have yapped you couldn't have yapped he couldn't have yapped we couldn't have yapped you couldn't have yapped they couldn't have yapped	I couldn't have been yapping you couldn't have been yapping he couldn't have been yapping we couldn't have been yapping you couldn't have been yapping they couldn't 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
couldn't I yap? couldn't you yap? couldn't he yap? couldn't we yap? couldn't you yap? couldn't they yap?	couldn't I be yapping? couldn't you be yapping? couldn't he be yapping? couldn't we be yapping? couldn't you be yapping? couldn't they be yapping?
Perfect	V-ing perfect
couldn't I have yapped? couldn't you have yapped? couldn't he have yapped? couldn't we have yapped? couldn't you have yapped? couldn't they have yapped?	couldn't I have been yapping? couldn't you have been yapping? couldn't he have been yapping? couldn't we have been yapping? couldn't you have been yapping? couldn't they have been yapping?