Present, Future 難しい is [x] 難しくない is not [x] Past 難しかった was [x] 難しくなかった was not [x] Te-form, Continuative 難しくて is [x] and... 難しくなくて is not [x] and... Provisional 難しければ if it is [x] 難しくなければ if it is not [x] Conditional 難しかったら when/if it is [x] 難しくなかったら when/if it is not [x] Adverbial 難しく [x]-ly Noun form 難しさ [x]-ness