The best time to plant a tree was 20 years ago. The second best time is now.
One way of looking at speech is to say that it is a constant stratagem to cover nakedness.
生物普遍存在的生存斗争不是为了原材料或能量,而是为了熵,它通过能量从炽热的太阳向寒冷的地球转移而变得可用。