jiǎ yǐ bǐng dīng / shì / xué xí / tiān gān / shí / zuì xiān / jì zhù / de / sì gè / zì

甲乙丙丁是学习天干时最先记住的四个字。

Jia, yi, bing, and ding are the first four characters you memorize when studying the Heavenly Stems.