The famous sentence in "Lime Song" is: Don't be afraid of broken bones and mud, but leave innocence in the world.

Brief analysis: Breaking into Pieces vividly describes that limestone is burnt into lime powder. The word "not afraid at all" reminds us that there may be a spirit of not being afraid of sacrifice. As for the last sentence "keep the world innocent", it is the author's sincere feelings and determination to be a pure and innocent person.