洞开

洞开	dòng kāi	to be wide open
洞	dòng	cave / hole / zero (unambiguous spoken form when spelling out numbers) / CL:个
洞	tóng	used in 洪洞, a county in Shanxi
开	kāi	to open (transitive or intransitive) / (of ships, vehicles, troops etc) to start / to turn on; to put in operation; to operate; to run / to boil / to write out (a prescription, check, invoice etc) / (directional complement) away; off / carat (gold) / abbr. for Kelvin, 开尔文 / abbr. for 开本, book format