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