1. Express different meanings: Good night: Definition of polite words to greet people at night or warm words before going to bed at night. An'an: Good night said by young people, more common among girls; it means to be content with the environment or habits; to be fair; to be stable; to be calm and peaceful; but in the cultures of Hong Kong, Taiwan and other regions, An'an can also be used as a daily greeting, or as a Say hello, strike up a conversation, etc.
2. Different sources: Good Night: From the 103rd chapter of "The Strange Situation I've Witnessed for Twenty Years", "I only suffered the misfortune of the second grandma. I have to return her wife's rules and go to ask for breakfast every day." Good afternoon, good night. "An'an: From a poem in "The Book of Songs", the first collection of ancient Chinese poems, "The Emperor is in a good mood" Come to capture the prisoners in groups, and cut off the enemy's ears peacefully and calmly)
3. Different usage scenarios: Good night: used for general evening greetings. An'an: Usually used for young people, and mostly for women.