I could dive you could dive he could dive we could dive you could dive they could dive
V-ing form
I could be diving you could be diving he could be diving we could be diving you could be diving they could be diving
Perfect
I could have dived you could have dived he could have dived we could have dived you could have dived they could have dived
V-ing perfect
I could have been diving you could have been diving he could have been diving we could have been diving you could have been diving they could have been diving
Negation
Simple form
I could not dive you could not dive he could not dive we could not dive you could not dive they could not dive
V-ing form
I could not be diving you could not be diving he could not be diving we could not be diving you could not be diving they could not be diving
Perfect
I could not have dived you could not have dived he could not have dived we could not have dived you could not have dived they could not have dived
V-ing perfect
I could not have been diving you could not have been diving he could not have been diving we could not have been diving you could not have been diving they could not have been diving
Interrogative form
Simple form
could I dive? could you dive? could he dive? could we dive? could you dive? could they dive?
V-ing form
could I be diving? could you be diving? could he be diving? could we be diving? could you be diving? could they be diving?
Perfect
could I have dived? could you have dived? could he have dived? could we have dived? could you have dived? could they have dived?
V-ing perfect
could I have been diving? could you have been diving? could he have been diving? could we have been diving? could you have been diving? could they have been diving?
Interro-negative form
Simple form
could I not dive? could you not dive? could he not dive? could we not dive? could you not dive? could they not dive?
V-ing form
could I not be diving? could you not be diving? could he not be diving? could we not be diving? could you not be diving? could they not be diving?
Perfect
could I not have dived? could you not have dived? could he not have dived? could we not have dived? could you not have dived? could they not have dived?
V-ing perfect
could I not have been diving? could you not have been diving? could he not have been diving? could we not have been diving? could you not have been diving? could they not have been diving?