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