English verb conjugation
COULD UNDERACHIEVE

Regular verb: underachieve - underachieved - underachieved

Affirmation

Simple form	V-ing form
I could underachieve you could underachieve he could underachieve we could underachieve you could underachieve they could underachieve	I could be underachieving you could be underachieving he could be underachieving we could be underachieving you could be underachieving they could be underachieving
Perfect	V-ing perfect
I could have underachieved you could have underachieved he could have underachieved we could have underachieved you could have underachieved they could have underachieved	I could have been underachieving you could have been underachieving he could have been underachieving we could have been underachieving you could have been underachieving they could have been underachieving

Negation

Simple form	V-ing form
I couldn't underachieve you couldn't underachieve he couldn't underachieve we couldn't underachieve you couldn't underachieve they couldn't underachieve	I couldn't be underachieving you couldn't be underachieving he couldn't be underachieving we couldn't be underachieving you couldn't be underachieving they couldn't be underachieving
Perfect	V-ing perfect
I couldn't have underachieved you couldn't have underachieved he couldn't have underachieved we couldn't have underachieved you couldn't have underachieved they couldn't have underachieved	I couldn't have been underachieving you couldn't have been underachieving he couldn't have been underachieving we couldn't have been underachieving you couldn't have been underachieving they couldn't have been underachieving

Interrogative form

Simple form	V-ing form
could I underachieve? could you underachieve? could he underachieve? could we underachieve? could you underachieve? could they underachieve?	could I be underachieving? could you be underachieving? could he be underachieving? could we be underachieving? could you be underachieving? could they be underachieving?
Perfect	V-ing perfect
could I have underachieved? could you have underachieved? could he have underachieved? could we have underachieved? could you have underachieved? could they have underachieved?	could I have been underachieving? could you have been underachieving? could he have been underachieving? could we have been underachieving? could you have been underachieving? could they have been underachieving?

Interro-negative form

Simple form	V-ing form
couldn't I underachieve? couldn't you underachieve? couldn't he underachieve? couldn't we underachieve? couldn't you underachieve? couldn't they underachieve?	couldn't I be underachieving? couldn't you be underachieving? couldn't he be underachieving? couldn't we be underachieving? couldn't you be underachieving? couldn't they be underachieving?
Perfect	V-ing perfect
couldn't I have underachieved? couldn't you have underachieved? couldn't he have underachieved? couldn't we have underachieved? couldn't you have underachieved? couldn't they have underachieved?	couldn't I have been underachieving? couldn't you have been underachieving? couldn't he have been underachieving? couldn't we have been underachieving? couldn't you have been underachieving? couldn't they have been underachieving?