Present, Future 根強い is [x] 根強くない is not [x] Past 根強かった was [x] 根強くなかった was not [x] Te-form, Continuative 根強くて is [x] and... 根強くなくて is not [x] and... Provisional 根強ければ if it is [x] 根強くなければ if it is not [x] Conditional 根強かったら when/if it is [x] 根強くなかったら when/if it is not [x] Adverbial 根強く [x]-ly Noun form 根強さ [x]-ness