1219. What character can be added to both of these characters to give other characters? 其_ -> _却

Answer:

其  shi, so - that

却  KYAKU - pull back, withdraw

Add 月:其+月 月+却 

月  GETSU, GATSU, tsuki - moon, month

期  KI, GO - time, period, term

脚  KYAKU, KYA, ashi - leg