I could plunge you could plunge he could plunge we could plunge you could plunge they could plunge
V-ing form
I could be plunging you could be plunging he could be plunging we could be plunging you could be plunging they could be plunging
Perfect
I could have plunged you could have plunged he could have plunged we could have plunged you could have plunged they could have plunged
V-ing perfect
I could have been plunging you could have been plunging he could have been plunging we could have been plunging you could have been plunging they could have been plunging
Negation
Simple form
I could not plunge you could not plunge he could not plunge we could not plunge you could not plunge they could not plunge
V-ing form
I could not be plunging you could not be plunging he could not be plunging we could not be plunging you could not be plunging they could not be plunging
Perfect
I could not have plunged you could not have plunged he could not have plunged we could not have plunged you could not have plunged they could not have plunged
V-ing perfect
I could not have been plunging you could not have been plunging he could not have been plunging we could not have been plunging you could not have been plunging they could not have been plunging
Interrogative form
Simple form
could I plunge? could you plunge? could he plunge? could we plunge? could you plunge? could they plunge?
V-ing form
could I be plunging? could you be plunging? could he be plunging? could we be plunging? could you be plunging? could they be plunging?
Perfect
could I have plunged? could you have plunged? could he have plunged? could we have plunged? could you have plunged? could they have plunged?
V-ing perfect
could I have been plunging? could you have been plunging? could he have been plunging? could we have been plunging? could you have been plunging? could they have been plunging?
Interro-negative form
Simple form
could I not plunge? could you not plunge? could he not plunge? could we not plunge? could you not plunge? could they not plunge?
V-ing form
could I not be plunging? could you not be plunging? could he not be plunging? could we not be plunging? could you not be plunging? could they not be plunging?
Perfect
could I not have plunged? could you not have plunged? could he not have plunged? could we not have plunged? could you not have plunged? could they not have plunged?
V-ing perfect
could I not have been plunging? could you not have been plunging? could he not have been plunging? could we not have been plunging? could you not have been plunging? could they not have been plunging?