English verb conjugation
COULD CALCULATE

Regular verb: calculate - calculated - calculated

Affirmation

Simple form	V-ing form
I could calculate you could calculate he could calculate we could calculate you could calculate they could calculate	I could be calculating you could be calculating he could be calculating we could be calculating you could be calculating they could be calculating
Perfect	V-ing perfect
I could have calculated you could have calculated he could have calculated we could have calculated you could have calculated they could have calculated	I could have been calculating you could have been calculating he could have been calculating we could have been calculating you could have been calculating they could have been calculating

Negation

Simple form	V-ing form
I could not calculate you could not calculate he could not calculate we could not calculate you could not calculate they could not calculate	I could not be calculating you could not be calculating he could not be calculating we could not be calculating you could not be calculating they could not be calculating
Perfect	V-ing perfect
I could not have calculated you could not have calculated he could not have calculated we could not have calculated you could not have calculated they could not have calculated	I could not have been calculating you could not have been calculating he could not have been calculating we could not have been calculating you could not have been calculating they could not have been calculating

Interrogative form

Simple form	V-ing form
could I calculate? could you calculate? could he calculate? could we calculate? could you calculate? could they calculate?	could I be calculating? could you be calculating? could he be calculating? could we be calculating? could you be calculating? could they be calculating?
Perfect	V-ing perfect
could I have calculated? could you have calculated? could he have calculated? could we have calculated? could you have calculated? could they have calculated?	could I have been calculating? could you have been calculating? could he have been calculating? could we have been calculating? could you have been calculating? could they have been calculating?

Interro-negative form

Simple form	V-ing form
could I not calculate? could you not calculate? could he not calculate? could we not calculate? could you not calculate? could they not calculate?	could I not be calculating? could you not be calculating? could he not be calculating? could we not be calculating? could you not be calculating? could they not be calculating?
Perfect	V-ing perfect
could I not have calculated? could you not have calculated? could he not have calculated? could we not have calculated? could you not have calculated? could they not have calculated?	could I not have been calculating? could you not have been calculating? could he not have been calculating? could we not have been calculating? could you not have been calculating? could they not have been calculating?