unknown [ˌʌnˈnəʊn]

以下由轻松背单词网站提供

adj.未知的，陌生的；n.未知的东西，未知数

not known or familiar

People usually infer an unknown fact from a known fact. 人们通常从已知的事实中推断未知的事实。
The scientist was faced with many unknown factors. 那个科学家面临许多未知数。