English verb conjugation
COULD SLIPPER

Regular verb: slipper - slippered - slippered

Affirmation

Simple form	V-ing form
I could slipper you could slipper he could slipper we could slipper you could slipper they could slipper	I could be slippering you could be slippering he could be slippering we could be slippering you could be slippering they could be slippering
Perfect	V-ing perfect
I could have slippered you could have slippered he could have slippered we could have slippered you could have slippered they could have slippered	I could have been slippering you could have been slippering he could have been slippering we could have been slippering you could have been slippering they could have been slippering

Negation

Simple form	V-ing form
I could not slipper you could not slipper he could not slipper we could not slipper you could not slipper they could not slipper	I could not be slippering you could not be slippering he could not be slippering we could not be slippering you could not be slippering they could not be slippering
Perfect	V-ing perfect
I could not have slippered you could not have slippered he could not have slippered we could not have slippered you could not have slippered they could not have slippered	I could not have been slippering you could not have been slippering he could not have been slippering we could not have been slippering you could not have been slippering they could not have been slippering

Interrogative form

Simple form	V-ing form
could I slipper? could you slipper? could he slipper? could we slipper? could you slipper? could they slipper?	could I be slippering? could you be slippering? could he be slippering? could we be slippering? could you be slippering? could they be slippering?
Perfect	V-ing perfect
could I have slippered? could you have slippered? could he have slippered? could we have slippered? could you have slippered? could they have slippered?	could I have been slippering? could you have been slippering? could he have been slippering? could we have been slippering? could you have been slippering? could they have been slippering?

Interro-negative form

Simple form	V-ing form
could I not slipper? could you not slipper? could he not slipper? could we not slipper? could you not slipper? could they not slipper?	could I not be slippering? could you not be slippering? could he not be slippering? could we not be slippering? could you not be slippering? could they not be slippering?
Perfect	V-ing perfect
could I not have slippered? could you not have slippered? could he not have slippered? could we not have slippered? could you not have slippered? could they not have slippered?	could I not have been slippering? could you not have been slippering? could he not have been slippering? could we not have been slippering? could you not have been slippering? could they not have been slippering?