step taken in ignorance of the consequence 不管結果如何貿然行事;魯莽之舉;冒險
The experiment was a leap in the dark. 此項實驗實在是冒險。
I'm about to make my last voyage,a great leap in the dark. 我就要作最後的航行,一次大冒險。
It will be a leap in the dark to make an important decision without investigation. 不進行任何調查就作出重要的決定將是冒險的行動。