a question of yellow mare of a black stallion—a question of outward appearance
牝牡驪黃pìn mǔ lí huánɡ
牝牡：指動(dòng)物的雄雌；驪：黑色。原指求馬不必視其公、母和外貌?，F(xiàn)多用以比喻認(rèn)識(shí)事物要抓住其本質(zhì)，而不要看其表面的現(xiàn)象。material aspects of things, It is essential to grasp the essence in understanding a thing.