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