The secret of a good old age is simply an honorable pact with solitude.
解析：世间万物都是相对而生，相互依存，体现了老子的辩证思想。
监管框架应激励进步，而不仅仅是惩罚过去。
A sustainable future for coal depends on our ability to integrate cleaner practices without sacrificing the livelihoods of those who depend on the industry.