171. Which one of these is the odd one out and what's the big deal about it? 陸 学 雨 事 根

Answer:

陸  RIKU - land

学  GAKU, mana(bu) - learn, study

雨  U, ame - rain

事  JI, koto - act, item

根  KON, ne - root, perseverance, origin

All take 大 (DAI, oo(kii) - big) in front to make a word, but only 雨 uses the "Oo" reading (Oo-ame); the others are all "Tai/Dai-": 大陸 TaiRiku, 大学 DaiGaku, 大事 DaiJi, 大根 DaiKon.