I could stand you could stand she could stand we could stand you could stand they could stand
V-ing form
I could be standing you could be standing she could be standing we could be standing you could be standing they could be standing
Perfect
I could have stood you could have stood she 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 she could have been standing we could have been standing you could have been standing they could have been standing
Negation
Simple form
I couldn't stand you couldn't stand she couldn't stand we couldn't stand you couldn't stand they couldn't stand
V-ing form
I couldn't be standing you couldn't be standing she couldn't be standing we couldn't be standing you couldn't be standing they couldn't be standing
Perfect
I couldn't have stood you couldn't have stood she couldn't have stood we couldn't have stood you couldn't have stood they couldn't have stood
V-ing perfect
I couldn't have been standing you couldn't have been standing she couldn't have been standing we couldn't have been standing you couldn't have been standing they couldn't have been standing
Interrogative form
Simple form
could I stand? could you stand? could she stand? could we stand? could you stand? could they stand?
V-ing form
could I be standing? could you be standing? could she be standing? could we be standing? could you be standing? could they be standing?
Perfect
could I have stood? could you have stood? could she 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 she have been standing? could we have been standing? could you have been standing? could they have been standing?
Interro-negative form
Simple form
couldn't I stand? couldn't you stand? couldn't she stand? couldn't we stand? couldn't you stand? couldn't they stand?
V-ing form
couldn't I be standing? couldn't you be standing? couldn't she be standing? couldn't we be standing? couldn't you be standing? couldn't they be standing?
Perfect
couldn't I have stood? couldn't you have stood? couldn't she have stood? couldn't we have stood? couldn't you have stood? couldn't they have stood?
V-ing perfect
couldn't I have been standing? couldn't you have been standing? couldn't she have been standing? couldn't we have been standing? couldn't you have been standing? couldn't they have been standing?