有关the past several years witnessed the phenomenon that ……时态问题

题目

有关the past several years witnessed the phenomenon that ……时态问题
请问是the past several years witnessed the phenomenon that还是the past several years have witnessed the phenomenon that 抑或the past several years has witnessed the phenomenon that
that后面要接什么时态的从句?
可以接it is difficult for us to live a safe life.

答案

用第二个：the past several years have witnessed the phenomenon that ...
原因：在句子中,把the past several years 拟人化,而这些年是一直在见证这个现象,故用完成时和复数.