a tiny aperture or opening through which it would seem impossible to pass (especially with reference to Matt. 19:24)
針眼；無(wú)法通過(guò)的開(kāi)口（尤指《馬太福音》１９：２４）
something that is almost impossible to find because it is hidden among so many other things
落進(jìn)草垛里的一根針（比喻很難找的東西）