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