1ADJ-GRADED [usually ADJ n](尤指问题或困难)永恒的,持续的,亘古不变的 You use perennial to describe situations or states that keep occurring or which seem to exist all the time; used especially to describe problems or difficulties. (尤指问题或困难)永恒的,持续的,亘古不变的
...the perennial urban problems of drugs and homelessness.
毒品和无家可归这两个一直困扰城市的问题
There's a perennial shortage of teachers with science qualifications.