2 sentences

1. 他们需要调查此事。

   tā​men xū​yào diào​chá cǐ​shì.

   They need to look into it.

   Source: OpenSubtitles

2. 我们必须尽快解决此事。

   wǒ​men bì​xū jǐn​kuài jiě​jué cǐ​shì.

   We must resolve this matter as quickly as possible.

   Source: Dong Chinese Dictionary