I could wallpaper you could wallpaper she could wallpaper we could wallpaper you could wallpaper they could wallpaper
V-ing form
I could be wallpapering you could be wallpapering she could be wallpapering we could be wallpapering you could be wallpapering they could be wallpapering
Perfect
I could have wallpapered you could have wallpapered she could have wallpapered we could have wallpapered you could have wallpapered they could have wallpapered
V-ing perfect
I could have been wallpapering you could have been wallpapering she could have been wallpapering we could have been wallpapering you could have been wallpapering they could have been wallpapering
Negation
Simple form
I could not wallpaper you could not wallpaper she could not wallpaper we could not wallpaper you could not wallpaper they could not wallpaper
V-ing form
I could not be wallpapering you could not be wallpapering she could not be wallpapering we could not be wallpapering you could not be wallpapering they could not be wallpapering
Perfect
I could not have wallpapered you could not have wallpapered she could not have wallpapered we could not have wallpapered you could not have wallpapered they could not have wallpapered
V-ing perfect
I could not have been wallpapering you could not have been wallpapering she could not have been wallpapering we could not have been wallpapering you could not have been wallpapering they could not have been wallpapering
Interrogative form
Simple form
could I wallpaper? could you wallpaper? could she wallpaper? could we wallpaper? could you wallpaper? could they wallpaper?
V-ing form
could I be wallpapering? could you be wallpapering? could she be wallpapering? could we be wallpapering? could you be wallpapering? could they be wallpapering?
Perfect
could I have wallpapered? could you have wallpapered? could she have wallpapered? could we have wallpapered? could you have wallpapered? could they have wallpapered?
V-ing perfect
could I have been wallpapering? could you have been wallpapering? could she have been wallpapering? could we have been wallpapering? could you have been wallpapering? could they have been wallpapering?
Interro-negative form
Simple form
could I not wallpaper? could you not wallpaper? could she not wallpaper? could we not wallpaper? could you not wallpaper? could they not wallpaper?
V-ing form
could I not be wallpapering? could you not be wallpapering? could she not be wallpapering? could we not be wallpapering? could you not be wallpapering? could they not be wallpapering?
Perfect
could I not have wallpapered? could you not have wallpapered? could she not have wallpapered? could we not have wallpapered? could you not have wallpapered? could they not have wallpapered?
V-ing perfect
could I not have been wallpapering? could you not have been wallpapering? could she not have been wallpapering? could we not have been wallpapering? could you not have been wallpapering? could they not have been wallpapering?