adv.永久地
Something that remains perennially fresh, interesting, or well liked. 经久不衰的事物常新的、百看不厌的或永保美名的事物
Permanently frozen subsoil, occurring throughout the Polar Regions and locally in perennially frigid areas. 永冻土永久冰冻的下层土壤，出现在整个北极地区和部分长期寒冷的地区
