The discovery of these tombs is of great significance for studying the history of the SHANG Dynasty
问题描述：
The discovery of these tombs is of great significance for studying the history of the SHANG Dynasty
of great significance 为什么不能换成great signficance great 不也是adj
答
与great 是不是adj 无关,is of great significance 中great significance 是形容词短语作名词
有一种固定结构用法：be of+名词
例如：The book is of a great value.其中的value就是名词