Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could forget forget you could forget forget he could forget forget we could forget forget you could forget forget they could forget forget
V-ing form
I could be forget forgeting you could be forget forgeting he could be forget forgeting we could be forget forgeting you could be forget forgeting they could be forget forgeting
Perfect
I could have forget forgeted you could have forget forgeted he could have forget forgeted we could have forget forgeted you could have forget forgeted they could have forget forgeted
V-ing perfect
I could have been forget forgeting you could have been forget forgeting he could have been forget forgeting we could have been forget forgeting you could have been forget forgeting they could have been forget forgeting
Negation
Simple form
I could not forget forget you could not forget forget he could not forget forget we could not forget forget you could not forget forget they could not forget forget
V-ing form
I could not be forget forgeting you could not be forget forgeting he could not be forget forgeting we could not be forget forgeting you could not be forget forgeting they could not be forget forgeting
Perfect
I could not have forget forgeted you could not have forget forgeted he could not have forget forgeted we could not have forget forgeted you could not have forget forgeted they could not have forget forgeted
V-ing perfect
I could not have been forget forgeting you could not have been forget forgeting he could not have been forget forgeting we could not have been forget forgeting you could not have been forget forgeting they could not have been forget forgeting
Interrogative form
Simple form
could I forget forget? could you forget forget? could he forget forget? could we forget forget? could you forget forget? could they forget forget?
V-ing form
could I be forget forgeting? could you be forget forgeting? could he be forget forgeting? could we be forget forgeting? could you be forget forgeting? could they be forget forgeting?
Perfect
could I have forget forgeted? could you have forget forgeted? could he have forget forgeted? could we have forget forgeted? could you have forget forgeted? could they have forget forgeted?
V-ing perfect
could I have been forget forgeting? could you have been forget forgeting? could he have been forget forgeting? could we have been forget forgeting? could you have been forget forgeting? could they have been forget forgeting?
Interro-negative form
Simple form
could I not forget forget? could you not forget forget? could he not forget forget? could we not forget forget? could you not forget forget? could they not forget forget?
V-ing form
could I not be forget forgeting? could you not be forget forgeting? could he not be forget forgeting? could we not be forget forgeting? could you not be forget forgeting? could they not be forget forgeting?
Perfect
could I not have forget forgeted? could you not have forget forgeted? could he not have forget forgeted? could we not have forget forgeted? could you not have forget forgeted? could they not have forget forgeted?
V-ing perfect
could I not have been forget forgeting? could you not have been forget forgeting? could he not have been forget forgeting? could we not have been forget forgeting? could you not have been forget forgeting? could they not have been forget forgeting?