2489. What characters can be added here so that each character contains a part of the previous character? a) 早 -> _ -> _ -> 現 b) 計 -> _ -> _ -> 球

a) 早 -> 古 -> 呈 -> 現  

早  SOU, SA, haya(i) , haya(meru) - early, fast, hasten

古  KO, furu(i) - old

呈  TEI - offer, present, exhibit

現  GEN, arawa(reru), arawa(su) - present, appear, show

b) 計 -> 古 -> 呈 -> 球  

計  KEI, haka(ru), haka(rau) - plan, total, measure

古  KO, furu(i) - old

呈  TEI - offer, present, exhibit

球  KYUU, tama - ball, sphere