This sentence came from 'Dream of the Red Chamber' written by Cao Xueqin in the Qing Dynasty. The original text was: " The moon in the sea is the moon in the sky. The person in front of me is my sweetheart. The heart is always the spectator. However, the person is the character in the drama." The meaning of this sentence was that the moon in the sea was the moon in the sky, and the person in front of him was the heart of everyone. The heart of everyone was the heart of the spectator, but the person was the character in the play. This sentence expressed people's perception and thinking about emotions and interpersonal relationships, revealing the complexity and variety of human nature.