(noun.) a variable whose values are solutions of an equation.
(noun.) an unknown and unexplored region; 'they came like angels out the unknown'.
(adj.) not known; 'an unknown amount'; 'an unknown island'; 'an unknown writer'; 'an unknown source' .
(adj.) not known to exist; 'things obscurely felt surged up from unknown depths' .
布什校对
汉克整理