The report that i'm reading is about ___ (change) in China over the past thirty years.

问题描述:

The report that i'm reading is about ___ (change) in China over the past thirty years.
为什么填的是 changes ,说明理由

我正读的这份报告是有关中国过去三十年的变化.
这里change是名词,变化,
三十年的变化不止一个,所以要用复数 changes