Present, Future 忘れられない is [x] 忘れられなくない is not [x] Past 忘れられなかった was [x] 忘れられなくなかった was not [x] Te-form, Continuative 忘れられなくて is [x] and... 忘れられなくなくて is not [x] and... Provisional 忘れられなければ if it is [x] 忘れられなくなければ if it is not [x] Conditional 忘れられなかったら when/if it is [x] 忘れられなくなかったら when/if it is not [x] Adverbial 忘れられなく [x]-ly Noun form 忘れられなさ [x]-ness