what从句处于评注性状语的位置，起评注性状语的作用，这种现象是很常见的。语料库有大量类似例句。现代语法书都将这种what从句分析为评注性状语。实际上，赵俊英的上述例句就是引自夸克《大全》（英文版 P 622）。

以下为COCA类似例句：

What is more important, the campaign for the elimination of the " fifth column " has raised the fear of persecution--so far mostly of losing jobs or normal business conditions--to a level not seen in the country since 1985.

What is more important, baseball taught us how to deal with failure -- hitless nights, slumps, losing streaks, subpar seasons, injuries, and demotions.

What is more important, it can help scientists develop insight into how the different dynamical processes involved in cell motility interact.

What is more significant, teachers of students with visual impairments have highly specialized expertise and are often the only professionals in their local education agencies who are knowledgeable about the impact of vision loss on learning.