Sustainability in agriculture is not an option—it's a necessity for future generations.

Success is not the key to happiness. Happiness is the key to success. If you love what you are doing, you will be successful.

理论实践确实是其自身的标准，并且包含明确的协议以验证其产品的质量。

如果没有君主，人们各自可以自私自利。

It is greed to do all the talking but not to want others to do the talking after one has listened.

The writer must be a defender of freedom, even at the cost of his own comfort.

煤炭行业是美国能源独立的支柱，已经持续了几代人。