English verb conjugation
COULD SIGH

Regular verb: sigh - sighed - sighed

Affirmation

Simple form	V-ing form
I could sigh you could sigh she could sigh we could sigh you could sigh they could sigh	I could be sighing you could be sighing she 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 she 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 she 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 couldn't sigh you couldn't sigh she couldn't sigh we couldn't sigh you couldn't sigh they couldn't sigh	I couldn't be sighing you couldn't be sighing she couldn't be sighing we couldn't be sighing you couldn't be sighing they couldn't be sighing
Perfect	V-ing perfect
I couldn't have sighed you couldn't have sighed she couldn't have sighed we couldn't have sighed you couldn't have sighed they couldn't have sighed	I couldn't have been sighing you couldn't have been sighing she couldn't have been sighing we couldn't have been sighing you couldn't have been sighing they couldn't have been sighing

Interrogative form

Simple form	V-ing form
could I sigh? could you sigh? could she sigh? could we sigh? could you sigh? could they sigh?	could I be sighing? could you be sighing? could she 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 she 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 she 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
couldn't I sigh? couldn't you sigh? couldn't she sigh? couldn't we sigh? couldn't you sigh? couldn't they sigh?	couldn't I be sighing? couldn't you be sighing? couldn't she be sighing? couldn't we be sighing? couldn't you be sighing? couldn't they be sighing?
Perfect	V-ing perfect
couldn't I have sighed? couldn't you have sighed? couldn't she have sighed? couldn't we have sighed? couldn't you have sighed? couldn't they have sighed?	couldn't I have been sighing? couldn't you have been sighing? couldn't she have been sighing? couldn't we have been sighing? couldn't you have been sighing? couldn't they have been sighing?