could underperform
Regular verb: underperform - underperformed- underperformed

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