I could assail you could assail she could assail we could assail you could assail they could assail
V-ing form
I could be assailing you could be assailing she could be assailing we could be assailing you could be assailing they could be assailing
Perfect
I could have assailed you could have assailed she could have assailed we could have assailed you could have assailed they could have assailed
V-ing perfect
I could have been assailing you could have been assailing she could have been assailing we could have been assailing you could have been assailing they could have been assailing
Negation
Simple form
I couldn't assail you couldn't assail she couldn't assail we couldn't assail you couldn't assail they couldn't assail
V-ing form
I couldn't be assailing you couldn't be assailing she couldn't be assailing we couldn't be assailing you couldn't be assailing they couldn't be assailing
Perfect
I couldn't have assailed you couldn't have assailed she couldn't have assailed we couldn't have assailed you couldn't have assailed they couldn't have assailed
V-ing perfect
I couldn't have been assailing you couldn't have been assailing she couldn't have been assailing we couldn't have been assailing you couldn't have been assailing they couldn't have been assailing
Interrogative form
Simple form
could I assail? could you assail? could she assail? could we assail? could you assail? could they assail?
V-ing form
could I be assailing? could you be assailing? could she be assailing? could we be assailing? could you be assailing? could they be assailing?
Perfect
could I have assailed? could you have assailed? could she have assailed? could we have assailed? could you have assailed? could they have assailed?
V-ing perfect
could I have been assailing? could you have been assailing? could she have been assailing? could we have been assailing? could you have been assailing? could they have been assailing?
Interro-negative form
Simple form
couldn't I assail? couldn't you assail? couldn't she assail? couldn't we assail? couldn't you assail? couldn't they assail?
V-ing form
couldn't I be assailing? couldn't you be assailing? couldn't she be assailing? couldn't we be assailing? couldn't you be assailing? couldn't they be assailing?
Perfect
couldn't I have assailed? couldn't you have assailed? couldn't she have assailed? couldn't we have assailed? couldn't you have assailed? couldn't they have assailed?
V-ing perfect
couldn't I have been assailing? couldn't you have been assailing? couldn't she have been assailing? couldn't we have been assailing? couldn't you have been assailing? couldn't they have been assailing?