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 couldn't believe you couldn't believe he couldn't believe we couldn't believe you couldn't believe they couldn't believe	I couldn't be believing you couldn't be believing he couldn't be believing we couldn't be believing you couldn't be believing they couldn't be believing
Perfect	V-ing perfect
I couldn't have believed you couldn't have believed he couldn't have believed we couldn't have believed you couldn't have believed they couldn't have believed	I couldn't have been believing you couldn't have been believing he couldn't have been believing we couldn't have been believing you couldn't have been believing they couldn't 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
couldn't I believe? couldn't you believe? couldn't he believe? couldn't we believe? couldn't you believe? couldn't they believe?	couldn't I be believing? couldn't you be believing? couldn't he be believing? couldn't we be believing? couldn't you be believing? couldn't they be believing?
Perfect	V-ing perfect
couldn't I have believed? couldn't you have believed? couldn't he have believed? couldn't we have believed? couldn't you have believed? couldn't they have believed?	couldn't I have been believing? couldn't you have been believing? couldn't he have been believing? couldn't we have been believing? couldn't you have been believing? couldn't they have been believing?