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