2 sentences

1. 反正保全也太严密了。

   fǎn​zheng bǎo​quán yě tài yán​mì le.

   The security is too tight anyway.

   Source: OpenSubtitles

2. 他们的存在是一个严密保护的秘密。

   tā​men de cún​zài shì yī​ge yán​mì bǎo​hù de mì​mì.

   Their existence is a closely guarded secret.

   Source: CCMatrix