1791. What character can be added to both of these characters to give other characters? 次_ -> _曽

Answer:

次  JI, tsugi, tsu(gu) - next

曽  SOU, katsute - overlap

Add 貝:次+貝 貝+曽 

貝  KAI - shellfish

資  SHI - resource, capital

贈  ZOU, SOU, oku(ru) - give, present, bestow