I could indulge you could indulge he could indulge we could indulge you could indulge they could indulge
V-ing form
I could be indulging you could be indulging he could be indulging we could be indulging you could be indulging they could be indulging
Perfect
I could have indulged you could have indulged he could have indulged we could have indulged you could have indulged they could have indulged
V-ing perfect
I could have been indulging you could have been indulging he could have been indulging we could have been indulging you could have been indulging they could have been indulging
Negation
Simple form
I could not indulge you could not indulge he could not indulge we could not indulge you could not indulge they could not indulge
V-ing form
I could not be indulging you could not be indulging he could not be indulging we could not be indulging you could not be indulging they could not be indulging
Perfect
I could not have indulged you could not have indulged he could not have indulged we could not have indulged you could not have indulged they could not have indulged
V-ing perfect
I could not have been indulging you could not have been indulging he could not have been indulging we could not have been indulging you could not have been indulging they could not have been indulging
Interrogative form
Simple form
could I indulge? could you indulge? could he indulge? could we indulge? could you indulge? could they indulge?
V-ing form
could I be indulging? could you be indulging? could he be indulging? could we be indulging? could you be indulging? could they be indulging?
Perfect
could I have indulged? could you have indulged? could he have indulged? could we have indulged? could you have indulged? could they have indulged?
V-ing perfect
could I have been indulging? could you have been indulging? could he have been indulging? could we have been indulging? could you have been indulging? could they have been indulging?
Interro-negative form
Simple form
could I not indulge? could you not indulge? could he not indulge? could we not indulge? could you not indulge? could they not indulge?
V-ing form
could I not be indulging? could you not be indulging? could he not be indulging? could we not be indulging? could you not be indulging? could they not be indulging?
Perfect
could I not have indulged? could you not have indulged? could he not have indulged? could we not have indulged? could you not have indulged? could they not have indulged?
V-ing perfect
could I not have been indulging? could you not have been indulging? could he not have been indulging? could we not have been indulging? could you not have been indulging? could they not have been indulging?