国家是理性的行为者，他们总是会按照自己的利益行事。
States are rational actors, and they will always act in their own self-interest.
你必须努力工作才能得到你想要的。
Sustainability isn't a trend—it's a responsibility we owe to future generations.
创造伟大事物的最佳方式是从小事开始。