I could brail you could brail he could brail we could brail you could brail they could brail
V-ing form
I could be brailing you could be brailing he could be brailing we could be brailing you could be brailing they could be brailing
Perfect
I could have brailed you could have brailed he could have brailed we could have brailed you could have brailed they could have brailed
V-ing perfect
I could have been brailing you could have been brailing he could have been brailing we could have been brailing you could have been brailing they could have been brailing
Negation
Simple form
I couldn't brail you couldn't brail he couldn't brail we couldn't brail you couldn't brail they couldn't brail
V-ing form
I couldn't be brailing you couldn't be brailing he couldn't be brailing we couldn't be brailing you couldn't be brailing they couldn't be brailing
Perfect
I couldn't have brailed you couldn't have brailed he couldn't have brailed we couldn't have brailed you couldn't have brailed they couldn't have brailed
V-ing perfect
I couldn't have been brailing you couldn't have been brailing he couldn't have been brailing we couldn't have been brailing you couldn't have been brailing they couldn't have been brailing
Interrogative form
Simple form
could I brail? could you brail? could he brail? could we brail? could you brail? could they brail?
V-ing form
could I be brailing? could you be brailing? could he be brailing? could we be brailing? could you be brailing? could they be brailing?
Perfect
could I have brailed? could you have brailed? could he have brailed? could we have brailed? could you have brailed? could they have brailed?
V-ing perfect
could I have been brailing? could you have been brailing? could he have been brailing? could we have been brailing? could you have been brailing? could they have been brailing?
Interro-negative form
Simple form
couldn't I brail? couldn't you brail? couldn't he brail? couldn't we brail? couldn't you brail? couldn't they brail?
V-ing form
couldn't I be brailing? couldn't you be brailing? couldn't he be brailing? couldn't we be brailing? couldn't you be brailing? couldn't they be brailing?
Perfect
couldn't I have brailed? couldn't you have brailed? couldn't he have brailed? couldn't we have brailed? couldn't you have brailed? couldn't they have brailed?
V-ing perfect
couldn't I have been brailing? couldn't you have been brailing? couldn't he have been brailing? couldn't we have been brailing? couldn't you have been brailing? couldn't they have been brailing?