English verb conjugation
COULD UNDERPERFORM

Regular verb: underperform - underperformed - underperformed

Affirmation

Simple form	V-ing form
I could underperform you could underperform she could underperform we could underperform you could underperform they could underperform	I could be underperforming you could be underperforming she could be underperforming we could be underperforming you could be underperforming they could be underperforming
Perfect	V-ing perfect
I could have underperformed you could have underperformed she could have underperformed we could have underperformed you could have underperformed they could have underperformed	I could have been underperforming you could have been underperforming she could have been underperforming we could have been underperforming you could have been underperforming they could have been underperforming

Negation

Simple form	V-ing form
I couldn't underperform you couldn't underperform she couldn't underperform we couldn't underperform you couldn't underperform they couldn't underperform	I couldn't be underperforming you couldn't be underperforming she couldn't be underperforming we couldn't be underperforming you couldn't be underperforming they couldn't be underperforming
Perfect	V-ing perfect
I couldn't have underperformed you couldn't have underperformed she couldn't have underperformed we couldn't have underperformed you couldn't have underperformed they couldn't have underperformed	I couldn't have been underperforming you couldn't have been underperforming she couldn't have been underperforming we couldn't have been underperforming you couldn't have been underperforming they couldn't have been underperforming

Interrogative form

Simple form	V-ing form
could I underperform? could you underperform? could she underperform? could we underperform? could you underperform? could they underperform?	could I be underperforming? could you be underperforming? could she be underperforming? could we be underperforming? could you be underperforming? could they be underperforming?
Perfect	V-ing perfect
could I have underperformed? could you have underperformed? could she have underperformed? could we have underperformed? could you have underperformed? could they have underperformed?	could I have been underperforming? could you have been underperforming? could she have been underperforming? could we have been underperforming? could you have been underperforming? could they have been underperforming?

Interro-negative form

Simple form	V-ing form
couldn't I underperform? couldn't you underperform? couldn't she underperform? couldn't we underperform? couldn't you underperform? couldn't they underperform?	couldn't I be underperforming? couldn't you be underperforming? couldn't she be underperforming? couldn't we be underperforming? couldn't you be underperforming? couldn't they be underperforming?
Perfect	V-ing perfect
couldn't I have underperformed? couldn't you have underperformed? couldn't she have underperformed? couldn't we have underperformed? couldn't you have underperformed? couldn't they have underperformed?	couldn't I have been underperforming? couldn't you have been underperforming? couldn't she have been underperforming? couldn't we have been underperforming? couldn't you have been underperforming? couldn't they have been underperforming?