可持续发展不是一种选择，而是现代经济中生存的必要条件。

If the job has been correctly done when a common stock is purchased, the time to sell it is—almost never.

I'm just a woman. And as a woman， I have no way to make money， not enough to earn a living and support my family. Even if I had my own money， which I don’t， it would belong to my husband the minute we were married. If we had children they would belong to him， not me. They would be his property. So don’t sit there and tell me that marriage isn’t an economic proposition， because it is.

我们都是时间旅行者，以生命的速度向前移动，但总是回头看。

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。