English verb conjugation
COULD NAIL

Regular verb: nail - nailed - nailed

Affirmation

Simple form	V-ing form
I could nail you could nail he could nail we could nail you could nail they could nail	I could be nailing you could be nailing he could be nailing we could be nailing you could be nailing they could be nailing
Perfect	V-ing perfect
I could have nailed you could have nailed he could have nailed we could have nailed you could have nailed they could have nailed	I could have been nailing you could have been nailing he could have been nailing we could have been nailing you could have been nailing they could have been nailing

Negation

Simple form	V-ing form
I could not nail you could not nail he could not nail we could not nail you could not nail they could not nail	I could not be nailing you could not be nailing he could not be nailing we could not be nailing you could not be nailing they could not be nailing
Perfect	V-ing perfect
I could not have nailed you could not have nailed he could not have nailed we could not have nailed you could not have nailed they could not have nailed	I could not have been nailing you could not have been nailing he could not have been nailing we could not have been nailing you could not have been nailing they could not have been nailing

Interrogative form

Simple form	V-ing form
could I nail? could you nail? could he nail? could we nail? could you nail? could they nail?	could I be nailing? could you be nailing? could he be nailing? could we be nailing? could you be nailing? could they be nailing?
Perfect	V-ing perfect
could I have nailed? could you have nailed? could he have nailed? could we have nailed? could you have nailed? could they have nailed?	could I have been nailing? could you have been nailing? could he have been nailing? could we have been nailing? could you have been nailing? could they have been nailing?

Interro-negative form

Simple form	V-ing form
could I not nail? could you not nail? could he not nail? could we not nail? could you not nail? could they not nail?	could I not be nailing? could you not be nailing? could he not be nailing? could we not be nailing? could you not be nailing? could they not be nailing?
Perfect	V-ing perfect
could I not have nailed? could you not have nailed? could he not have nailed? could we not have nailed? could you not have nailed? could they not have nailed?	could I not have been nailing? could you not have been nailing? could he not have been nailing? could we not have been nailing? could you not have been nailing? could they not have been nailing?