I could blink you could blink she could blink we could blink you could blink they could blink
V-ing form
I could be blinking you could be blinking she could be blinking we could be blinking you could be blinking they could be blinking
Perfect
I could have blinked you could have blinked she 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 she 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 she 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 she 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 she 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 she 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 she blink? could we blink? could you blink? could they blink?
V-ing form
could I be blinking? could you be blinking? could she be blinking? could we be blinking? could you be blinking? could they be blinking?
Perfect
could I have blinked? could you have blinked? could she 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 she 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 she 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 she 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 she 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 she have been blinking? couldn't we have been blinking? couldn't you have been blinking? couldn't they have been blinking?