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