2396. What characters can be added here so that each character contains a part of the previous character? a) 婆 -> _ -> _ -> 坪 b) 誓 -> _ -> _ -> 吹

a) 婆 -> 如 -> 吐 -> 坪  

婆  BA - old woman

如  JO, NYO - equal, like, as, as if

吐  TOU, ha(ku) - spew, vomit, give vent to

坪  tsubo - unit of area

b) 誓 -> 計 -> 古 -> 吹  

誓  SEI, chika(u) - swear, pledge, vow

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

古  KO, furu(i) - old

吹  SUI, fu(ku) - blow