1401. What character can be added to both of these characters to give other characters? 士_ -> _鳥

Answer:

士  SHI - samurai, man, scholar

鳥  CHOU, tori - bird 

Add 口:士+口 口+鳥 

口  KOU, kuchi - mouth

吉  KICHI, KITSU, yoshi - good luck

鳴  MEI, na(ku), na(ru)(rasu) - cry, sing, howl, ring