English verb conjugation
COULD UNDERESTIMATE

Regular verb: underestimate - underestimated - underestimated

Affirmation

Simple form	V-ing form
I could underestimate you could underestimate he could underestimate we could underestimate you could underestimate they could underestimate	I could be underestimating you could be underestimating he could be underestimating we could be underestimating you could be underestimating they could be underestimating
Perfect	V-ing perfect
I could have underestimated you could have underestimated he could have underestimated we could have underestimated you could have underestimated they could have underestimated	I could have been underestimating you could have been underestimating he could have been underestimating we could have been underestimating you could have been underestimating they could have been underestimating

Negation

Simple form	V-ing form
I couldn't underestimate you couldn't underestimate he couldn't underestimate we couldn't underestimate you couldn't underestimate they couldn't underestimate	I couldn't be underestimating you couldn't be underestimating he couldn't be underestimating we couldn't be underestimating you couldn't be underestimating they couldn't be underestimating
Perfect	V-ing perfect
I couldn't have underestimated you couldn't have underestimated he couldn't have underestimated we couldn't have underestimated you couldn't have underestimated they couldn't have underestimated	I couldn't have been underestimating you couldn't have been underestimating he couldn't have been underestimating we couldn't have been underestimating you couldn't have been underestimating they couldn't have been underestimating

Interrogative form

Simple form	V-ing form
could I underestimate? could you underestimate? could he underestimate? could we underestimate? could you underestimate? could they underestimate?	could I be underestimating? could you be underestimating? could he be underestimating? could we be underestimating? could you be underestimating? could they be underestimating?
Perfect	V-ing perfect
could I have underestimated? could you have underestimated? could he have underestimated? could we have underestimated? could you have underestimated? could they have underestimated?	could I have been underestimating? could you have been underestimating? could he have been underestimating? could we have been underestimating? could you have been underestimating? could they have been underestimating?

Interro-negative form

Simple form	V-ing form
couldn't I underestimate? couldn't you underestimate? couldn't he underestimate? couldn't we underestimate? couldn't you underestimate? couldn't they underestimate?	couldn't I be underestimating? couldn't you be underestimating? couldn't he be underestimating? couldn't we be underestimating? couldn't you be underestimating? couldn't they be underestimating?
Perfect	V-ing perfect
couldn't I have underestimated? couldn't you have underestimated? couldn't he have underestimated? couldn't we have underestimated? couldn't you have underestimated? couldn't they have underestimated?	couldn't I have been underestimating? couldn't you have been underestimating? couldn't he have been underestimating? couldn't we have been underestimating? couldn't you have been underestimating? couldn't they have been underestimating?