bié / zài / kè / rén / miàn / qián / dà / shēng / xuān / huá / miǎn / de / ràng / rén / jué / de / nǐ / shì / tǔ / bā / lǎo

别在客人面前大声喧哗，免得让人觉得你是土巴佬。

Don't shout in front of the guests, or people may think you have no manners.