The scientist confirmed the snake was a previously unknown species after conducting a genetic analysis of tissue samples.
出自-2017年6月听力原文
According to Leslie, those who ridiculed former Defense Secretary Donald Rumsfeld for his 2002 remark that we have to be wary of the unknown unknowns were mistaken.
2017年12月四级真题(第二套)阅读 Section B
英语六级真题
What distinguishes a depression from a harsh recession is paralyzing fear - fear of the unknown so great that it causes consumers, businesses, and investors to retreat and panic.
出自-2013年6月阅读原文
These "thought experiments" were pages of calculations signed and submitted to the prestigious journal Annalen der Physik by a virtual unknown.
出自-2010年12月阅读原文
Into the Unknown The world has never seen population ageing before
出自-2010年12月阅读原文
柯林斯高阶英汉双解学习词典释义
ADJ
不知道的;不了解的;未知的
If something is unknown to you, you have no knowledge of it.