phenomenon
可观察的事件或情况(义项一)
occurrence
发生的事,事件(更通用,不含「值得研究」的暗示)
Scientists are studying the phenomenon of microplastic accumulation in deep-sea ecosystems.
科学家正在研究深海生态系统中微塑料积累的现象。
Rainfall is a common occurrence in this region during the monsoon season.
降雨是季风季节该地区的常见现象。