He found his hometown greatly changed.

问题描述:

He found his hometown greatly changed.
这里changed是过去分词吗?为什么用被动?家乡改变不是应该用主动吗?

是过去分词 ,但不是表被动而是表过去完成时、
这个句子是宾语+宾补结构 his hometown是宾语 greatly changed 是宾补
另 这个句子为方便理解可转化为宾语从句:he found that his hometown great had greatly changed.