English verb conjugation
COULD ZIPPER

Regular verb: zipper - zippered - zippered

Affirmation

Simple form	V-ing form
I could zipper you could zipper he could zipper we could zipper you could zipper they could zipper	I could be zippering you could be zippering he could be zippering we could be zippering you could be zippering they could be zippering
Perfect	V-ing perfect
I could have zippered you could have zippered he could have zippered we could have zippered you could have zippered they could have zippered	I could have been zippering you could have been zippering he could have been zippering we could have been zippering you could have been zippering they could have been zippering

Negation

Simple form	V-ing form
I could not zipper you could not zipper he could not zipper we could not zipper you could not zipper they could not zipper	I could not be zippering you could not be zippering he could not be zippering we could not be zippering you could not be zippering they could not be zippering
Perfect	V-ing perfect
I could not have zippered you could not have zippered he could not have zippered we could not have zippered you could not have zippered they could not have zippered	I could not have been zippering you could not have been zippering he could not have been zippering we could not have been zippering you could not have been zippering they could not have been zippering

Interrogative form

Simple form	V-ing form
could I zipper? could you zipper? could he zipper? could we zipper? could you zipper? could they zipper?	could I be zippering? could you be zippering? could he be zippering? could we be zippering? could you be zippering? could they be zippering?
Perfect	V-ing perfect
could I have zippered? could you have zippered? could he have zippered? could we have zippered? could you have zippered? could they have zippered?	could I have been zippering? could you have been zippering? could he have been zippering? could we have been zippering? could you have been zippering? could they have been zippering?

Interro-negative form

Simple form	V-ing form
could I not zipper? could you not zipper? could he not zipper? could we not zipper? could you not zipper? could they not zipper?	could I not be zippering? could you not be zippering? could he not be zippering? could we not be zippering? could you not be zippering? could they not be zippering?
Perfect	V-ing perfect
could I not have zippered? could you not have zippered? could he not have zippered? could we not have zippered? could you not have zippered? could they not have zippered?	could I not have been zippering? could you not have been zippering? could he not have been zippering? could we not have been zippering? could you not have been zippering? could they not have been zippering?