把这一句，留给此刻的你

Science cuts two ways, of course; its products can be used for both good and evil. But there's no turning back from science.

当然，科学有两条路可走;它的产品可以用来做好事，也可以用来做坏事。但科学是没有回头路的。

— Carl Sagan 卡尔·萨根