2 sentences

1. 这种专业性很强的工作，你可千万不能乱来。

   zhè zhǒng zhuān​yè​xìng hěn qiáng de gōng​zuò, nǐ kě qiān​wàn bù néng luàn​lái.

   This is a highly professional job; you must not mess around.

   Source: Dong Chinese Dictionary

2. 他因为在外面跟人乱来，结果毁了自己的名声。

   tā yīn​wèi zài wài​miàn gēn rén luàn​lái, jié​guǒ huǐ le zì​jǐ de míng​shēng.

   He ruined his reputation because he was fooling around with people outside.

   Source: Dong Chinese Dictionary