3 sentences

1. 我们无从得知。

   wǒ​men wú​cóng dé​zhī.

   We have no way of knowing.

   Source: OpenSubtitles

2. 由于这是高度机密，普通职员无从得知详细情况。

   yóu​yú zhè shì gāo​dù jī​mì, pǔ​tōng zhí​yuán wú​cóng dé​zhī xiáng​xì qíng​kuàng.

   Since it is highly confidential, ordinary staff have no way of knowing the details.

   Source: Dong Chinese Dictionary

3. 面对这么多杂乱的线索，警察感到无从下手。

   miàn​duì zhè​me duō zá​luàn de xiàn​suǒ, jǐng​chá gǎn​dào wú​cóng xià​shǒu.

   Faced with so many tangled clues, the police felt at a loss for where to start.

   Source: Dong Chinese Dictionary