English verb conjugation
COULD OVERESTIMATE

Regular verb: overestimate - overestimated - overestimated

Affirmation

Simple form	V-ing form
I could overestimate you could overestimate he could overestimate we could overestimate you could overestimate they could overestimate	I could be overestimating you could be overestimating he could be overestimating we could be overestimating you could be overestimating they could be overestimating
Perfect	V-ing perfect
I could have overestimated you could have overestimated he could have overestimated we could have overestimated you could have overestimated they could have overestimated	I could have been overestimating you could have been overestimating he could have been overestimating we could have been overestimating you could have been overestimating they could have been overestimating

Negation

Simple form	V-ing form
I could not overestimate you could not overestimate he could not overestimate we could not overestimate you could not overestimate they could not overestimate	I could not be overestimating you could not be overestimating he could not be overestimating we could not be overestimating you could not be overestimating they could not be overestimating
Perfect	V-ing perfect
I could not have overestimated you could not have overestimated he could not have overestimated we could not have overestimated you could not have overestimated they could not have overestimated	I could not have been overestimating you could not have been overestimating he could not have been overestimating we could not have been overestimating you could not have been overestimating they could not have been overestimating

Interrogative form

Simple form	V-ing form
could I overestimate? could you overestimate? could he overestimate? could we overestimate? could you overestimate? could they overestimate?	could I be overestimating? could you be overestimating? could he be overestimating? could we be overestimating? could you be overestimating? could they be overestimating?
Perfect	V-ing perfect
could I have overestimated? could you have overestimated? could he have overestimated? could we have overestimated? could you have overestimated? could they have overestimated?	could I have been overestimating? could you have been overestimating? could he have been overestimating? could we have been overestimating? could you have been overestimating? could they have been overestimating?

Interro-negative form

Simple form	V-ing form
could I not overestimate? could you not overestimate? could he not overestimate? could we not overestimate? could you not overestimate? could they not overestimate?	could I not be overestimating? could you not be overestimating? could he not be overestimating? could we not be overestimating? could you not be overestimating? could they not be overestimating?
Perfect	V-ing perfect
could I not have overestimated? could you not have overestimated? could he not have overestimated? could we not have overestimated? could you not have overestimated? could they not have overestimated?	could I not have been overestimating? could you not have been overestimating? could he not have been overestimating? could we not have been overestimating? could you not have been overestimating? could they not have been overestimating?