I could photograph you could photograph he could photograph we could photograph you could photograph they could photograph
V-ing form
I could be photographing you could be photographing he could be photographing we could be photographing you could be photographing they could be photographing
Perfect
I could have photographed you could have photographed he could have photographed we could have photographed you could have photographed they could have photographed
V-ing perfect
I could have been photographing you could have been photographing he could have been photographing we could have been photographing you could have been photographing they could have been photographing
Negation
Simple form
I couldn't photograph you couldn't photograph he couldn't photograph we couldn't photograph you couldn't photograph they couldn't photograph
V-ing form
I couldn't be photographing you couldn't be photographing he couldn't be photographing we couldn't be photographing you couldn't be photographing they couldn't be photographing
Perfect
I couldn't have photographed you couldn't have photographed he couldn't have photographed we couldn't have photographed you couldn't have photographed they couldn't have photographed
V-ing perfect
I couldn't have been photographing you couldn't have been photographing he couldn't have been photographing we couldn't have been photographing you couldn't have been photographing they couldn't have been photographing
Interrogative form
Simple form
could I photograph? could you photograph? could he photograph? could we photograph? could you photograph? could they photograph?
V-ing form
could I be photographing? could you be photographing? could he be photographing? could we be photographing? could you be photographing? could they be photographing?
Perfect
could I have photographed? could you have photographed? could he have photographed? could we have photographed? could you have photographed? could they have photographed?
V-ing perfect
could I have been photographing? could you have been photographing? could he have been photographing? could we have been photographing? could you have been photographing? could they have been photographing?
Interro-negative form
Simple form
couldn't I photograph? couldn't you photograph? couldn't he photograph? couldn't we photograph? couldn't you photograph? couldn't they photograph?
V-ing form
couldn't I be photographing? couldn't you be photographing? couldn't he be photographing? couldn't we be photographing? couldn't you be photographing? couldn't they be photographing?
Perfect
couldn't I have photographed? couldn't you have photographed? couldn't he have photographed? couldn't we have photographed? couldn't you have photographed? couldn't they have photographed?
V-ing perfect
couldn't I have been photographing? couldn't you have been photographing? couldn't he have been photographing? couldn't we have been photographing? couldn't you have been photographing? couldn't they have been photographing?