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