The most precious thing is life. There is only one life. Therefore, one's life should be spent like this: when one looks back on the past, one will not regret for wasting one's time, and will not be ashamed for being mediocre; In this way, when he died, it can be said that I devoted all my life and energy to the most valuable cause in life-the struggle for the liberation of mankind. We must make use of our life time, because even if we suddenly get sick or terminate our life unexpectedly.