辛苦了 (xīnkǔ le) is one of the most common polite phrases in Chinese. Say it to anyone who has just finished work or done something effortful — like the Japanese お疲れ様 (otsukaresama).
usage
辛苦 can be an adjective (这工作很辛苦) or used as a polite expression (辛苦你了). It's warmer and more personal than a simple 谢谢.
