I could undergo you could undergo she could undergo we could undergo you could undergo they could undergo
V-ing form
I could be undergoing you could be undergoing she could be undergoing we could be undergoing you could be undergoing they could be undergoing
Perfect
I could have undergone you could have undergone she could have undergone we could have undergone you could have undergone they could have undergone
V-ing perfect
I could have been undergoing you could have been undergoing she could have been undergoing we could have been undergoing you could have been undergoing they could have been undergoing
Negation
Simple form
I could not undergo you could not undergo she could not undergo we could not undergo you could not undergo they could not undergo
V-ing form
I could not be undergoing you could not be undergoing she could not be undergoing we could not be undergoing you could not be undergoing they could not be undergoing
Perfect
I could not have undergone you could not have undergone she could not have undergone we could not have undergone you could not have undergone they could not have undergone
V-ing perfect
I could not have been undergoing you could not have been undergoing she could not have been undergoing we could not have been undergoing you could not have been undergoing they could not have been undergoing
Interrogative form
Simple form
could I undergo? could you undergo? could she undergo? could we undergo? could you undergo? could they undergo?
V-ing form
could I be undergoing? could you be undergoing? could she be undergoing? could we be undergoing? could you be undergoing? could they be undergoing?
Perfect
could I have undergone? could you have undergone? could she have undergone? could we have undergone? could you have undergone? could they have undergone?
V-ing perfect
could I have been undergoing? could you have been undergoing? could she have been undergoing? could we have been undergoing? could you have been undergoing? could they have been undergoing?
Interro-negative form
Simple form
could I not undergo? could you not undergo? could she not undergo? could we not undergo? could you not undergo? could they not undergo?
V-ing form
could I not be undergoing? could you not be undergoing? could she not be undergoing? could we not be undergoing? could you not be undergoing? could they not be undergoing?
Perfect
could I not have undergone? could you not have undergone? could she not have undergone? could we not have undergone? could you not have undergone? could they not have undergone?
V-ing perfect
could I not have been undergoing? could you not have been undergoing? could she not have been undergoing? could we not have been undergoing? could you not have been undergoing? could they not have been undergoing?