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