I could cook you could cook he could cook we could cook you could cook they could cook
V-ing form
I could be cooking you could be cooking he could be cooking we could be cooking you could be cooking they could be cooking
Perfect
I could have cooked you could have cooked he could have cooked we could have cooked you could have cooked they could have cooked
V-ing perfect
I could have been cooking you could have been cooking he could have been cooking we could have been cooking you could have been cooking they could have been cooking
Negation
Simple form
I could not cook you could not cook he could not cook we could not cook you could not cook they could not cook
V-ing form
I could not be cooking you could not be cooking he could not be cooking we could not be cooking you could not be cooking they could not be cooking
Perfect
I could not have cooked you could not have cooked he could not have cooked we could not have cooked you could not have cooked they could not have cooked
V-ing perfect
I could not have been cooking you could not have been cooking he could not have been cooking we could not have been cooking you could not have been cooking they could not have been cooking
Interrogative form
Simple form
could I cook? could you cook? could he cook? could we cook? could you cook? could they cook?
V-ing form
could I be cooking? could you be cooking? could he be cooking? could we be cooking? could you be cooking? could they be cooking?
Perfect
could I have cooked? could you have cooked? could he have cooked? could we have cooked? could you have cooked? could they have cooked?
V-ing perfect
could I have been cooking? could you have been cooking? could he have been cooking? could we have been cooking? could you have been cooking? could they have been cooking?
Interro-negative form
Simple form
could I not cook? could you not cook? could he not cook? could we not cook? could you not cook? could they not cook?
V-ing form
could I not be cooking? could you not be cooking? could he not be cooking? could we not be cooking? could you not be cooking? could they not be cooking?
Perfect
could I not have cooked? could you not have cooked? could he not have cooked? could we not have cooked? could you not have cooked? could they not have cooked?
V-ing perfect
could I not have been cooking? could you not have been cooking? could he not have been cooking? could we not have been cooking? could you not have been cooking? could they not have been cooking?