English verb conjugation
COULD SIGH

Regular verb: sigh - sighed - sighed

Affirmation

Simple form	V-ing form
I could sigh you could sigh he could sigh we could sigh you could sigh they could sigh	I could be sighing you could be sighing he could be sighing we could be sighing you could be sighing they could be sighing
Perfect	V-ing perfect
I could have sighed you could have sighed he could have sighed we could have sighed you could have sighed they could have sighed	I could have been sighing you could have been sighing he could have been sighing we could have been sighing you could have been sighing they could have been sighing

Negation

Simple form	V-ing form
I could not sigh you could not sigh he could not sigh we could not sigh you could not sigh they could not sigh	I could not be sighing you could not be sighing he could not be sighing we could not be sighing you could not be sighing they could not be sighing
Perfect	V-ing perfect
I could not have sighed you could not have sighed he could not have sighed we could not have sighed you could not have sighed they could not have sighed	I could not have been sighing you could not have been sighing he could not have been sighing we could not have been sighing you could not have been sighing they could not have been sighing

Interrogative form

Simple form	V-ing form
could I sigh? could you sigh? could he sigh? could we sigh? could you sigh? could they sigh?	could I be sighing? could you be sighing? could he be sighing? could we be sighing? could you be sighing? could they be sighing?
Perfect	V-ing perfect
could I have sighed? could you have sighed? could he have sighed? could we have sighed? could you have sighed? could they have sighed?	could I have been sighing? could you have been sighing? could he have been sighing? could we have been sighing? could you have been sighing? could they have been sighing?

Interro-negative form

Simple form	V-ing form
could I not sigh? could you not sigh? could he not sigh? could we not sigh? could you not sigh? could they not sigh?	could I not be sighing? could you not be sighing? could he not be sighing? could we not be sighing? could you not be sighing? could they not be sighing?
Perfect	V-ing perfect
could I not have sighed? could you not have sighed? could he not have sighed? could we not have sighed? could you not have sighed? could they not have sighed?	could I not have been sighing? could you not have been sighing? could he not have been sighing? could we not have been sighing? could you not have been sighing? could they not have been sighing?