I could aid you could aid he could aid we could aid you could aid they could aid
V-ing form
I could be aiding you could be aiding he could be aiding we could be aiding you could be aiding they could be aiding
Perfect
I could have aided you could have aided he could have aided we could have aided you could have aided they could have aided
V-ing perfect
I could have been aiding you could have been aiding he could have been aiding we could have been aiding you could have been aiding they could have been aiding
Negation
Simple form
I could not aid you could not aid he could not aid we could not aid you could not aid they could not aid
V-ing form
I could not be aiding you could not be aiding he could not be aiding we could not be aiding you could not be aiding they could not be aiding
Perfect
I could not have aided you could not have aided he could not have aided we could not have aided you could not have aided they could not have aided
V-ing perfect
I could not have been aiding you could not have been aiding he could not have been aiding we could not have been aiding you could not have been aiding they could not have been aiding
Interrogative form
Simple form
could I aid? could you aid? could he aid? could we aid? could you aid? could they aid?
V-ing form
could I be aiding? could you be aiding? could he be aiding? could we be aiding? could you be aiding? could they be aiding?
Perfect
could I have aided? could you have aided? could he have aided? could we have aided? could you have aided? could they have aided?
V-ing perfect
could I have been aiding? could you have been aiding? could he have been aiding? could we have been aiding? could you have been aiding? could they have been aiding?
Interro-negative form
Simple form
could I not aid? could you not aid? could he not aid? could we not aid? could you not aid? could they not aid?
V-ing form
could I not be aiding? could you not be aiding? could he not be aiding? could we not be aiding? could you not be aiding? could they not be aiding?
Perfect
could I not have aided? could you not have aided? could he not have aided? could we not have aided? could you not have aided? could they not have aided?
V-ing perfect
could I not have been aiding? could you not have been aiding? could he not have been aiding? could we not have been aiding? could you not have been aiding? could they not have been aiding?