The historian is a prophet looking backwards.
历史学家是向后看的先知。
病毒的复杂性提醒我们，关于生物学我们还有很多需要学习。
Art is a matter of life and death. This could be my last message.
What you actually pay for something is at least twice the listed price because of the energy， time， money needed to set it up， learn， maintain， repair， and dispose of at the end. Not all prices appear on labels. Actual costs are 2x listed prices.