Chuántǒng de wèishēngqiú zhǔyào chéngfèn jiùshì nài.
The main ingredient of old-fashioned mothballs is naphthalene.
Tips
memory
萘 (nài) is a phono-semantic compound: the 艹 (grass) radical signals it comes from organic/plant-derived material (originally distilled from coal tar), and 奈 lends a near-homophone reading. Think: a chemistry term that wears a leafy hat.
culture
Naphthalene is the chemistry behind the classic Chinese 卫生球 (wèishēngqiú, mothballs) once kept in every wardrobe — that sharp, distinctive smell is 萘.
