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