3 sentences

1. 他可能已经死了也未可知。

   tā kě​néng yǐ​jīng sǐ le yě wèi kě​zhī.

   He could be dead, for all I know.

   Source: OpenSubtitles

2. 那次行动的成败犹未可知。

   nà cì xíng​dòng de chéng​bài yóu wèi kě zhī.

   The success or failure of that operation is still unknown.

   Source: Dong Chinese Dictionary

3. 本届世界杯群雄逐鹿，谁能夺冠尚未可知。

   běn jiè Shì​jiè​bēi qún​xióng zhú​lù, shéi néng duó​guàn shàng wèi kě zhī.

   The giants are competing in this World Cup; it's still unknown who will win.

   Source: Dong Chinese Dictionary