Summary: The philosopher said: Cherish life! There are only three days in life: yesterday, today and tomorrow. Yesterday, today, and tomorrow constitute the annual rings of time and the "three steps" of life. Those who forget yesterday will not cherish today, and those who waste today will not value tomorrow. Thinking about yesterday will make you deep; grasping today will make you full; looking forward to tomorrow will make your mind wider and your vision farther away. However, if you just sigh for yesterday's inaction, then tomorrow you will be sad for today's nothing; similarly, if you just live in the fantasy of tomorrow. Then, tomorrow will only bring you another disappointment. Yesterday, today, tomorrow, the most important thing is to seize today and seize every minute and second in reality, which is better than ten years and hundreds of years indulging in dreams. Smart people examine yesterday, seize today, and plan for tomorrow. Foolish people lament yesterday, squander today, dream about tomorrow, and ultimately waste their lives in confusion. A meaningful and valuable life should be: a yesterday with no regrets, a fruitful today, and a tomorrow full of hope.