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