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