I could succeed you could succeed he could succeed we could succeed you could succeed they could succeed
V-ing form
I could be succeeding you could be succeeding he could be succeeding we could be succeeding you could be succeeding they could be succeeding
Perfect
I could have succeeded you could have succeeded he could have succeeded we could have succeeded you could have succeeded they could have succeeded
V-ing perfect
I could have been succeeding you could have been succeeding he could have been succeeding we could have been succeeding you could have been succeeding they could have been succeeding
Negation
Simple form
I could not succeed you could not succeed he could not succeed we could not succeed you could not succeed they could not succeed
V-ing form
I could not be succeeding you could not be succeeding he could not be succeeding we could not be succeeding you could not be succeeding they could not be succeeding
Perfect
I could not have succeeded you could not have succeeded he could not have succeeded we could not have succeeded you could not have succeeded they could not have succeeded
V-ing perfect
I could not have been succeeding you could not have been succeeding he could not have been succeeding we could not have been succeeding you could not have been succeeding they could not have been succeeding
Interrogative form
Simple form
could I succeed? could you succeed? could he succeed? could we succeed? could you succeed? could they succeed?
V-ing form
could I be succeeding? could you be succeeding? could he be succeeding? could we be succeeding? could you be succeeding? could they be succeeding?
Perfect
could I have succeeded? could you have succeeded? could he have succeeded? could we have succeeded? could you have succeeded? could they have succeeded?
V-ing perfect
could I have been succeeding? could you have been succeeding? could he have been succeeding? could we have been succeeding? could you have been succeeding? could they have been succeeding?
Interro-negative form
Simple form
could I not succeed? could you not succeed? could he not succeed? could we not succeed? could you not succeed? could they not succeed?
V-ing form
could I not be succeeding? could you not be succeeding? could he not be succeeding? could we not be succeeding? could you not be succeeding? could they not be succeeding?
Perfect
could I not have succeeded? could you not have succeeded? could he not have succeeded? could we not have succeeded? could you not have succeeded? could they not have succeeded?
V-ing perfect
could I not have been succeeding? could you not have been succeeding? could he not have been succeeding? could we not have been succeeding? could you not have been succeeding? could they not have been succeeding?