perennial plant多年生植物;[植] 多年生植物
perennial river常流河;常年河;常年性河流;四季不枯竭的河流
perennial stream[地理] 常流河;常劣;常流;常年河川
Perennial Sunflower野生向日葵;野生向葵;家死背日葵;生日花野生向日葵
perennial chamomile黄金菊;黄金菊介绍
Perennial vegetable多年生蔬菜
perennial grass多年生牧草;多年生禾草;多年生草;多年生植物
perennial algae多年生藻类
perennial herb多年生草本;多年生草本植物
Conclusion: The vocational environment is related with the allergic to dust mites in the patients of perennial allergic rhinitis among different occupational groups in Huainan . The labor protection should be strengthened to the specific occupational groups.
结论：淮南地区不同职业中常年性变应性鼻炎患者对尘螨的过敏情况与职业环境有关，应加强对特定职业人群的劳动保护。
参考来源 - 淮南地区常年性变应性鼻炎对尘螨过敏情况的调查—《中国医药导报》—2008年第4期—龙源期刊网ADJ（形容词） You use perennial to describe situations or states that keep occurring or that seem to exist all the time; used especially to describe problems or difficulties. 不断出现的; 长期存在的 (问题、困难)
...the perennial urban problems of drugs and homelessness.
…城市长期存在的毒品和无家可归的问题。
ADJ（形容词） A perennial plant lives for several years and has flowers each year. (植物) 多年生的
...a perennial herb with greenish-yellow flowers.
…一种开黄绿色花的多年生草本植物。
N-COUNT（可数名词） Perennial is also a noun. 多年生植物
...a low-growing perennial.
…一种长不高的多年生植物。