English verb conjugation
COULD RAIL

Regular verb: rail - railed - railed

Affirmation

Simple form	V-ing form
I could rail you could rail he could rail we could rail you could rail they could rail	I could be railing you could be railing he could be railing we could be railing you could be railing they could be railing
Perfect	V-ing perfect
I could have railed you could have railed he could have railed we could have railed you could have railed they could have railed	I could have been railing you could have been railing he could have been railing we could have been railing you could have been railing they could have been railing

Negation

Simple form	V-ing form
I couldn't rail you couldn't rail he couldn't rail we couldn't rail you couldn't rail they couldn't rail	I couldn't be railing you couldn't be railing he couldn't be railing we couldn't be railing you couldn't be railing they couldn't be railing
Perfect	V-ing perfect
I couldn't have railed you couldn't have railed he couldn't have railed we couldn't have railed you couldn't have railed they couldn't have railed	I couldn't have been railing you couldn't have been railing he couldn't have been railing we couldn't have been railing you couldn't have been railing they couldn't have been railing

Interrogative form

Simple form	V-ing form
could I rail? could you rail? could he rail? could we rail? could you rail? could they rail?	could I be railing? could you be railing? could he be railing? could we be railing? could you be railing? could they be railing?
Perfect	V-ing perfect
could I have railed? could you have railed? could he have railed? could we have railed? could you have railed? could they have railed?	could I have been railing? could you have been railing? could he have been railing? could we have been railing? could you have been railing? could they have been railing?

Interro-negative form

Simple form	V-ing form
couldn't I rail? couldn't you rail? couldn't he rail? couldn't we rail? couldn't you rail? couldn't they rail?	couldn't I be railing? couldn't you be railing? couldn't he be railing? couldn't we be railing? couldn't you be railing? couldn't they be railing?
Perfect	V-ing perfect
couldn't I have railed? couldn't you have railed? couldn't he have railed? couldn't we have railed? couldn't you have railed? couldn't they have railed?	couldn't I have been railing? couldn't you have been railing? couldn't he have been railing? couldn't we have been railing? couldn't you have been railing? couldn't they have been railing?