Slow onset of the disease, with the cyclical increase mitigation, many for several years, the slow process of evolution.

本病起病缓慢，呈周期性加重与减轻，多有数年的缓慢演变过程。

youdao

The history of biosis is the longtime process of succession characterizing the cyclical features of the succession and evolution of plant communities: succession-differentiation-extinction-evolution.

生命的历史是漫长攸久的演替过程表征着植物群落演替进化的周期性特征，即“演替-分化-灭绝-突变-进化”的过程。

youdao