By used books. They have the same words as the new ones. Also libraries.
仅仅那山学会下一而是不够的,种大需里当上如有阳光、自由,和一点花的芬芳。
The future of coal lies in clean and efficient utilization.
别相信你听到的任何事情,看到的也只信一半。
科学的进步不仅通过知识的积累来衡量,还通过提出新问题的能力来衡量。