I could ulcerate you could ulcerate he could ulcerate we could ulcerate you could ulcerate they could ulcerate
V-ing form
I could be ulcerating you could be ulcerating he could be ulcerating we could be ulcerating you could be ulcerating they could be ulcerating
Perfect
I could have ulcerated you could have ulcerated he could have ulcerated we could have ulcerated you could have ulcerated they could have ulcerated
V-ing perfect
I could have been ulcerating you could have been ulcerating he could have been ulcerating we could have been ulcerating you could have been ulcerating they could have been ulcerating
Negation
Simple form
I could not ulcerate you could not ulcerate he could not ulcerate we could not ulcerate you could not ulcerate they could not ulcerate
V-ing form
I could not be ulcerating you could not be ulcerating he could not be ulcerating we could not be ulcerating you could not be ulcerating they could not be ulcerating
Perfect
I could not have ulcerated you could not have ulcerated he could not have ulcerated we could not have ulcerated you could not have ulcerated they could not have ulcerated
V-ing perfect
I could not have been ulcerating you could not have been ulcerating he could not have been ulcerating we could not have been ulcerating you could not have been ulcerating they could not have been ulcerating
Interrogative form
Simple form
could I ulcerate? could you ulcerate? could he ulcerate? could we ulcerate? could you ulcerate? could they ulcerate?
V-ing form
could I be ulcerating? could you be ulcerating? could he be ulcerating? could we be ulcerating? could you be ulcerating? could they be ulcerating?
Perfect
could I have ulcerated? could you have ulcerated? could he have ulcerated? could we have ulcerated? could you have ulcerated? could they have ulcerated?
V-ing perfect
could I have been ulcerating? could you have been ulcerating? could he have been ulcerating? could we have been ulcerating? could you have been ulcerating? could they have been ulcerating?
Interro-negative form
Simple form
could I not ulcerate? could you not ulcerate? could he not ulcerate? could we not ulcerate? could you not ulcerate? could they not ulcerate?
V-ing form
could I not be ulcerating? could you not be ulcerating? could he not be ulcerating? could we not be ulcerating? could you not be ulcerating? could they not be ulcerating?
Perfect
could I not have ulcerated? could you not have ulcerated? could he not have ulcerated? could we not have ulcerated? could you not have ulcerated? could they not have ulcerated?
V-ing perfect
could I not have been ulcerating? could you not have been ulcerating? could he not have been ulcerating? could we not have been ulcerating? could you not have been ulcerating? could they not have been ulcerating?