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