English verb conjugation
COULD SIUM

Regular verb: sium - siumed - siumed

Affirmation

Simple form	V-ing form
I could sium you could sium he could sium we could sium you could sium they could sium	I could be siuming you could be siuming he could be siuming we could be siuming you could be siuming they could be siuming
Perfect	V-ing perfect
I could have siumed you could have siumed he could have siumed we could have siumed you could have siumed they could have siumed	I could have been siuming you could have been siuming he could have been siuming we could have been siuming you could have been siuming they could have been siuming

Negation

Simple form	V-ing form
I could not sium you could not sium he could not sium we could not sium you could not sium they could not sium	I could not be siuming you could not be siuming he could not be siuming we could not be siuming you could not be siuming they could not be siuming
Perfect	V-ing perfect
I could not have siumed you could not have siumed he could not have siumed we could not have siumed you could not have siumed they could not have siumed	I could not have been siuming you could not have been siuming he could not have been siuming we could not have been siuming you could not have been siuming they could not have been siuming

Interrogative form

Simple form	V-ing form
could I sium? could you sium? could he sium? could we sium? could you sium? could they sium?	could I be siuming? could you be siuming? could he be siuming? could we be siuming? could you be siuming? could they be siuming?
Perfect	V-ing perfect
could I have siumed? could you have siumed? could he have siumed? could we have siumed? could you have siumed? could they have siumed?	could I have been siuming? could you have been siuming? could he have been siuming? could we have been siuming? could you have been siuming? could they have been siuming?

Interro-negative form

Simple form	V-ing form
could I not sium? could you not sium? could he not sium? could we not sium? could you not sium? could they not sium?	could I not be siuming? could you not be siuming? could he not be siuming? could we not be siuming? could you not be siuming? could they not be siuming?
Perfect	V-ing perfect
could I not have siumed? could you not have siumed? could he not have siumed? could we not have siumed? could you not have siumed? could they not have siumed?	could I not have been siuming? could you not have been siuming? could he not have been siuming? could we not have been siuming? could you not have been siuming? could they not have been siuming?