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