English verb conjugation
COULD BELIEVE

Regular verb: believe - believed - believed

Affirmation

Simple form	V-ing form
I could believe you could believe he could believe we could believe you could believe they could believe	I could be believing you could be believing he could be believing we could be believing you could be believing they could be believing
Perfect	V-ing perfect
I could have believed you could have believed he could have believed we could have believed you could have believed they could have believed	I could have been believing you could have been believing he could have been believing we could have been believing you could have been believing they could have been believing

Negation

Simple form	V-ing form
I could not believe you could not believe he could not believe we could not believe you could not believe they could not believe	I could not be believing you could not be believing he could not be believing we could not be believing you could not be believing they could not be believing
Perfect	V-ing perfect
I could not have believed you could not have believed he could not have believed we could not have believed you could not have believed they could not have believed	I could not have been believing you could not have been believing he could not have been believing we could not have been believing you could not have been believing they could not have been believing

Interrogative form

Simple form	V-ing form
could I believe? could you believe? could he believe? could we believe? could you believe? could they believe?	could I be believing? could you be believing? could he be believing? could we be believing? could you be believing? could they be believing?
Perfect	V-ing perfect
could I have believed? could you have believed? could he have believed? could we have believed? could you have believed? could they have believed?	could I have been believing? could you have been believing? could he have been believing? could we have been believing? could you have been believing? could they have been believing?

Interro-negative form

Simple form	V-ing form
could I not believe? could you not believe? could he not believe? could we not believe? could you not believe? could they not believe?	could I not be believing? could you not be believing? could he not be believing? could we not be believing? could you not be believing? could they not be believing?
Perfect	V-ing perfect
could I not have believed? could you not have believed? could he not have believed? could we not have believed? could you not have believed? could they not have believed?	could I not have been believing? could you not have been believing? could he not have been believing? could we not have been believing? could you not have been believing? could they not have been believing?