perennialadj.永久的；反复出现的；多年生的n.多年生植物perennial pattern经典模式perennial-frost多年冻土perennial grasses多年生牧草perennial alfalfa生草覆盖perennial rhinitis常年性鼻炎perennial ryegrass黑麦草perennial organism多年生生物Perennial allergic常年性变态反应性鼻炎perennial exhibitor常年展览厂商perennial overdraft(地下水的) 常年过量抽取