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