Signing the contract without reading the fine print would be sheer folly.

沒看清楚細則就簽約，簡直是愚蠢至極。

The board agreed that expanding overseas during the recession was an expensive folly.

董事會一致認為，在經濟衰退期間拓展海外市場是一項代價高昂的愚行。

It is folly to book a connecting flight with only thirty minutes between gates.

轉機時間只留三十分鐘就訂票，實在很不明智。