I could ensure you could ensure she could ensure we could ensure you could ensure they could ensure
V-ing form
I could be ensuring you could be ensuring she could be ensuring we could be ensuring you could be ensuring they could be ensuring
Perfect
I could have ensured you could have ensured she could have ensured we could have ensured you could have ensured they could have ensured
V-ing perfect
I could have been ensuring you could have been ensuring she could have been ensuring we could have been ensuring you could have been ensuring they could have been ensuring
Negation
Simple form
I could not ensure you could not ensure she could not ensure we could not ensure you could not ensure they could not ensure
V-ing form
I could not be ensuring you could not be ensuring she could not be ensuring we could not be ensuring you could not be ensuring they could not be ensuring
Perfect
I could not have ensured you could not have ensured she could not have ensured we could not have ensured you could not have ensured they could not have ensured
V-ing perfect
I could not have been ensuring you could not have been ensuring she could not have been ensuring we could not have been ensuring you could not have been ensuring they could not have been ensuring
Interrogative form
Simple form
could I ensure? could you ensure? could she ensure? could we ensure? could you ensure? could they ensure?
V-ing form
could I be ensuring? could you be ensuring? could she be ensuring? could we be ensuring? could you be ensuring? could they be ensuring?
Perfect
could I have ensured? could you have ensured? could she have ensured? could we have ensured? could you have ensured? could they have ensured?
V-ing perfect
could I have been ensuring? could you have been ensuring? could she have been ensuring? could we have been ensuring? could you have been ensuring? could they have been ensuring?
Interro-negative form
Simple form
could I not ensure? could you not ensure? could she not ensure? could we not ensure? could you not ensure? could they not ensure?
V-ing form
could I not be ensuring? could you not be ensuring? could she not be ensuring? could we not be ensuring? could you not be ensuring? could they not be ensuring?
Perfect
could I not have ensured? could you not have ensured? could she not have ensured? could we not have ensured? could you not have ensured? could they not have ensured?
V-ing perfect
could I not have been ensuring? could you not have been ensuring? could she not have been ensuring? could we not have been ensuring? could you not have been ensuring? could they not have been ensuring?