English verb conjugation
COULD QUIVER

Regular verb: quiver - quivered - quivered

Affirmation

Simple form	V-ing form
I could quiver you could quiver he could quiver we could quiver you could quiver they could quiver	I could be quivering you could be quivering he could be quivering we could be quivering you could be quivering they could be quivering
Perfect	V-ing perfect
I could have quivered you could have quivered he could have quivered we could have quivered you could have quivered they could have quivered	I could have been quivering you could have been quivering he could have been quivering we could have been quivering you could have been quivering they could have been quivering

Negation

Simple form	V-ing form
I could not quiver you could not quiver he could not quiver we could not quiver you could not quiver they could not quiver	I could not be quivering you could not be quivering he could not be quivering we could not be quivering you could not be quivering they could not be quivering
Perfect	V-ing perfect
I could not have quivered you could not have quivered he could not have quivered we could not have quivered you could not have quivered they could not have quivered	I could not have been quivering you could not have been quivering he could not have been quivering we could not have been quivering you could not have been quivering they could not have been quivering

Interrogative form

Simple form	V-ing form
could I quiver? could you quiver? could he quiver? could we quiver? could you quiver? could they quiver?	could I be quivering? could you be quivering? could he be quivering? could we be quivering? could you be quivering? could they be quivering?
Perfect	V-ing perfect
could I have quivered? could you have quivered? could he have quivered? could we have quivered? could you have quivered? could they have quivered?	could I have been quivering? could you have been quivering? could he have been quivering? could we have been quivering? could you have been quivering? could they have been quivering?

Interro-negative form

Simple form	V-ing form
could I not quiver? could you not quiver? could he not quiver? could we not quiver? could you not quiver? could they not quiver?	could I not be quivering? could you not be quivering? could he not be quivering? could we not be quivering? could you not be quivering? could they not be quivering?
Perfect	V-ing perfect
could I not have quivered? could you not have quivered? could he not have quivered? could we not have quivered? could you not have quivered? could they not have quivered?	could I not have been quivering? could you not have been quivering? could he not have been quivering? could we not have been quivering? could you not have been quivering? could they not have been quivering?