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