perennial       
 adjective uk/pəˈren.i.əl/ us/pəˈren.i.əl/
 长期存在的;常年的;不断发生的;反复的
lasting a very long time, or happening repeatedly or all the time
  The film "White Christmas" is a perennial favourite. 《白色圣诞》是一部经久不衰、深受欢迎的影片。 
 We face the perennial problem of not having enough money. 我们长期面临资金不足的问题。 
 Compare: annual adjectivebiennial adjective
 perennial       
noun [ C ] uk/pəˈren.i.əl/ us/pəˈren.i.əl/
 多年生植物
a plant that lives for several years
  Roses and geraniums are perennials, flowering year after year. 玫瑰和天竺葵是多年生植物,年复一年地开花。 
 Compare: annual noun (PLANT)