I could grimace you could grimace he could grimace we could grimace you could grimace they could grimace
V-ing form
I could be grimacing you could be grimacing he could be grimacing we could be grimacing you could be grimacing they could be grimacing
Perfect
I could have grimaced you could have grimaced he could have grimaced we could have grimaced you could have grimaced they could have grimaced
V-ing perfect
I could have been grimacing you could have been grimacing he could have been grimacing we could have been grimacing you could have been grimacing they could have been grimacing
Negation
Simple form
I could not grimace you could not grimace he could not grimace we could not grimace you could not grimace they could not grimace
V-ing form
I could not be grimacing you could not be grimacing he could not be grimacing we could not be grimacing you could not be grimacing they could not be grimacing
Perfect
I could not have grimaced you could not have grimaced he could not have grimaced we could not have grimaced you could not have grimaced they could not have grimaced
V-ing perfect
I could not have been grimacing you could not have been grimacing he could not have been grimacing we could not have been grimacing you could not have been grimacing they could not have been grimacing
Interrogative form
Simple form
could I grimace? could you grimace? could he grimace? could we grimace? could you grimace? could they grimace?
V-ing form
could I be grimacing? could you be grimacing? could he be grimacing? could we be grimacing? could you be grimacing? could they be grimacing?
Perfect
could I have grimaced? could you have grimaced? could he have grimaced? could we have grimaced? could you have grimaced? could they have grimaced?
V-ing perfect
could I have been grimacing? could you have been grimacing? could he have been grimacing? could we have been grimacing? could you have been grimacing? could they have been grimacing?
Interro-negative form
Simple form
could I not grimace? could you not grimace? could he not grimace? could we not grimace? could you not grimace? could they not grimace?
V-ing form
could I not be grimacing? could you not be grimacing? could he not be grimacing? could we not be grimacing? could you not be grimacing? could they not be grimacing?
Perfect
could I not have grimaced? could you not have grimaced? could he not have grimaced? could we not have grimaced? could you not have grimaced? could they not have grimaced?
V-ing perfect
could I not have been grimacing? could you not have been grimacing? could he not have been grimacing? could we not have been grimacing? could you not have been grimacing? could they not have been grimacing?