3 sentences

1. 这是个密室。

   zhè shì gè mì​shì.

   This is a secret room.

   Source: OpenSubtitles

2. 还是先解开密室之谜比较好吧。

   hái​shi xiān jiě​kāi mì​shì zhī mí bǐ​jiào hǎo ba.

   Maybe we should solve the locked room mystery first.

   Source: OpenSubtitles

3. 他在书架后面发现了一个隐藏的密室。

   tā zài shū​jià hòu​mian fā​xiàn le yī gè yǐn​cáng de mì​shì.

   He discovered a hidden chamber behind the bookshelf.

   Source: Dong Chinese Dictionary