The last paragraph of the text, Cicada, used a metaphor to compare the life of cicadas with that of human beings, emphasizing that the preciousness and shortness of life had an enlightening and inspiring effect. Metaphor was a rhetorical device that emphasized the similarities between two things by comparing them to express the author's views and emotions more deeply. In the text, Cicada, the author emphasized the preciousness and shortness of life by comparing cicadas with human life, so that people would cherish life and time more. At the same time, this way of expression could also stimulate the readers 'thoughts and feelings, guiding them to think about the essence and meaning of life.