I could paint you could paint he could paint we could paint you could paint they could paint
V-ing form
I could be painting you could be painting he could be painting we could be painting you could be painting they could be painting
Perfect
I could have painted you could have painted he could have painted we could have painted you could have painted they could have painted
V-ing perfect
I could have been painting you could have been painting he could have been painting we could have been painting you could have been painting they could have been painting
Negation
Simple form
I could not paint you could not paint he could not paint we could not paint you could not paint they could not paint
V-ing form
I could not be painting you could not be painting he could not be painting we could not be painting you could not be painting they could not be painting
Perfect
I could not have painted you could not have painted he could not have painted we could not have painted you could not have painted they could not have painted
V-ing perfect
I could not have been painting you could not have been painting he could not have been painting we could not have been painting you could not have been painting they could not have been painting
Interrogative form
Simple form
could I paint? could you paint? could he paint? could we paint? could you paint? could they paint?
V-ing form
could I be painting? could you be painting? could he be painting? could we be painting? could you be painting? could they be painting?
Perfect
could I have painted? could you have painted? could he have painted? could we have painted? could you have painted? could they have painted?
V-ing perfect
could I have been painting? could you have been painting? could he have been painting? could we have been painting? could you have been painting? could they have been painting?
Interro-negative form
Simple form
could I not paint? could you not paint? could he not paint? could we not paint? could you not paint? could they not paint?
V-ing form
could I not be painting? could you not be painting? could he not be painting? could we not be painting? could you not be painting? could they not be painting?
Perfect
could I not have painted? could you not have painted? could he not have painted? could we not have painted? could you not have painted? could they not have painted?
V-ing perfect
could I not have been painting? could you not have been painting? could he not have been painting? could we not have been painting? could you not have been painting? could they not have been painting?