perennial

交通拥堵是这个城市的永恒问题。

Traffic congestion is a ___perennial issue in this city.

玫瑰是多年生植物，每年春天都会重新开花。

Roses are ___perennial plants that bloom again every spring.

她对学习的热情是持久的，从未因时间而减弱。

Her ___perennial enthusiasm for learning never fades with time.