积极情绪不是微不足道的奢侈品，而是最佳功能的关键必需品。
Positive emotions are not trivial luxuries, but instead may be critical necessities for optimal functioning.
The spread of liberal democracy has been accompanied by the spread of a global culture that is increasingly homogeneous.
We must mine coal responsibly today so that our children inherit both energy security and a healthy environment.
写作是关于创造一些东西，而不是表达自己。