七八十岁的人,就算思想豁达,脑中也会常常出现一个驱之不散的阴影:我到底还能活多久?这不是害怕死,而是想知道还能有多少时间享受生活,争取在可知的时间里尽可能多做一些想做的事。我自己经常就有这样的想法。按理说,到了八十岁,就是长寿了,已经比许多人多活许多年了,还不知足吗?记得初唐的王勃和中唐的李贺,他们都只不过活到二十七岁,杜甫也不过活到五十九岁,就寿命而言,比起我们来要差得远了,也不幸多了。这是生命的量化计算,一般都是用这种算法来估算寿命的。从生理学的角度 People in their seventies and seventies, even when they are open-minded, often have a long-awaited shadow in their brains: how long can I live in the end? This is not to fear death, but to know how much time I can enjoy to live and fight Do as much as you want in the knowable time. I often have this idea myself. It stands to reason that by the age of eighty, that is, longevity, many people have lived more than many years, but still not satisfied? Remember Wang Bo in early Tang Dynasty and Li He in the middle of the Tang Dynasty, they only lived until twenty-seven, Du Fu also lived to fifty-nine years of age, in terms of life expectancy, far worse than us, but also unlucky. This is a quantitative calculation of life, which is generally used to estimate life expectancy. From the physiological point of view