Every ton of coal we extract carries equal weight in responsibility.
我们开采的每一吨煤炭都承载着同等重量的责任。
过去是一个跟随我们的影子，一个困扰我们的幽灵。
书籍是通往其他生活的窗户。
The most important thing in science is not so much to obtain new facts as to discover new ways of thinking about them.
It is not the benevolence of the employer that determines the wages of labor， but the competition among employers.
