I could stand you could stand he could stand we could stand you could stand they could stand
V-ing form
I could be standing you could be standing he could be standing we could be standing you could be standing they could be standing
Perfect
I could have stood you could have stood he could have stood we could have stood you could have stood they could have stood
V-ing perfect
I could have been standing you could have been standing he could have been standing we could have been standing you could have been standing they could have been standing
Negation
Simple form
I could not stand you could not stand he could not stand we could not stand you could not stand they could not stand
V-ing form
I could not be standing you could not be standing he could not be standing we could not be standing you could not be standing they could not be standing
Perfect
I could not have stood you could not have stood he could not have stood we could not have stood you could not have stood they could not have stood
V-ing perfect
I could not have been standing you could not have been standing he could not have been standing we could not have been standing you could not have been standing they could not have been standing
Interrogative form
Simple form
could I stand? could you stand? could he stand? could we stand? could you stand? could they stand?
V-ing form
could I be standing? could you be standing? could he be standing? could we be standing? could you be standing? could they be standing?
Perfect
could I have stood? could you have stood? could he have stood? could we have stood? could you have stood? could they have stood?
V-ing perfect
could I have been standing? could you have been standing? could he have been standing? could we have been standing? could you have been standing? could they have been standing?
Interro-negative form
Simple form
could I not stand? could you not stand? could he not stand? could we not stand? could you not stand? could they not stand?
V-ing form
could I not be standing? could you not be standing? could he not be standing? could we not be standing? could you not be standing? could they not be standing?
Perfect
could I not have stood? could you not have stood? could he not have stood? could we not have stood? could you not have stood? could they not have stood?
V-ing perfect
could I not have been standing? could you not have been standing? could he not have been standing? could we not have been standing? could you not have been standing? could they not have been standing?