English verb conjugation
CAN UNDERPERFORM

Regular verb: underperform - underperformed - underperformed

Affirmation

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

Negation

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

Interrogative form

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

Interro-negative form

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