Looking back 500 years, what is the song of laughter in 1?

Looking back 500 times in my last life, laughing 1, what did you get? In the novel Looking Back, this sentence appears more than 1 time. I would like to be a stone bridge, which will be blown by the wind for 500 years, exposed to the sun for 500 years and rained for 500 years, just asking her to cross the bridge "means 1! There are 500 views of the original post in the lyrics >>