What do you mean when you say that the past is like a dream?
Let those beautiful things stay in memory and turn around and continue to struggle. According to the inquiry of Sohu Education Network, once upon a time, singing was like a dream and turning around like a million waters. Qianshan means: just leave those beautiful things in your memory, turn around and continue to struggle, and keep trying what you might like, and spend time and energy until you find what you really like, and make efforts and persistence to turn it into something you are good at.