But there is also time for brief diversions onto bizarre ground, such as a discussion of the skyscraper index (which holds that a boom in skyscraper construction is a foolproof sign of an imminent recessio.
出自-2013年6月阅读原文
柯林斯高阶英汉双解学习词典释义
ADJ-GRADED
(计划、机器等)十分简单的，容易操作的，万无一失的
Something such as a plan or a machine that is foolproof is so well designed, easy to understand, or easy to use that it cannot go wrong or be used wrongly.