介词of与名词importance（重要性）之间,可以用表示程度的形容词来加强语气,如：of great importance.significant在这里意思与great 类似,表示“非常,极度,及其”.
e.g.This book is of great importance to me.这本书对我来说非常重要.
Water is of significant importance to human being.水对人类至关重要.
另外,如果将Importance换成形容词Important的话,只需要将前面的形容词换成副词即可：
of significant importance = significantly important