2 sentences

1. 你一定要安静，好吗？

   nǐ yī​dìng​yào ān​jìng, hǎo​ma?

   You must be quiet, okay?

   Source: AI Challenger 2017

2. 保持冷静，好吗？

   bǎo​chí lěng​jìng, hǎo​ma?

   Stay calm, okay?

   Source: OpenSubtitles