2 sentences

1. 这个奥秘始终未得到解释。

   zhè​ge ào​mì shǐ​zhōng wèi dé dào jiě​shì.

   This mystery has never been explained.

   Source: CCMatrix

2. 我们这个星球的历史充满了令人难以置信的奥秘。

   wǒ​men zhè​ge xīng​qiú de lì​shǐ chōng​mǎn le lìng​rén nán​yǐ​zhì​xìn de ào​mì.

   The history of our planet is full of incredible mysteries.

   Source: CCMatrix