light at the end of the tunnel 的词源

比喻义，“长久以来追寻的目标或终点即将实现的希望之 signs”，自1879年起。字面义，指铁路隧道，早在1833年。

Sometimes we have an experience in life that seems like walking through a long, dark tunnel. ... We can only fix our eyes on the bright light at the end of the tunnel, and we comfort ourselves with the thought that every step we take brings us nearer to the joy and the rest that lies at the end of the way. ["Trusting God in the Dark," sermon printed in several U.S. newspapers late 1881, credited to Presbyterian minister Theodore L. Cuyler]

有时候，我们在人生中会经历一段像是走过漫长黑暗隧道的旅程。……我们只能将目光锁定在隧道尽头的明亮光芒上，并安慰自己，每一步都将我们带向那份在旅程尽头的喜悦与安宁。[“在黑暗中信靠上帝”，1881年底在美国多家报纸上印发的布道，归功于长老会牧师西奥多·L·凯勒]