死者从未真正离去，他们只是改变了形态。
The dead are never really gone, they just change form.
The most important political development of the last half century has been the spread of liberal democracy around the world.
The life of man is of no greater importance to the universe than that of an oyster.
无人机的安全性不是选项，而是底线。
如果我们致力于正确的技术，可持续的煤炭行业是可能的。