钻故纸堆 zuāngùzhǐduī to pore over ancient books Origin Definitions Defs Strokes Stroke Words Sentences Sents 钻 鑽 zuān to study intensively to dig into a subject; to study or research deeply; to devote oneself to a specialty故纸堆 故紙堆 gùzhǐduī pile of old books a heap of musty old books or historical documents