自然实验可以为经济问题提供有价值的见解。
Natural experiments can provide valuable insights into economic questions.
You are never too old to set another goal or to dream a new dream.
天然气开采的创新是满足世界日益增长的能源需求的关键。
I want to inspire people to follow their dreams.
政策应该基于证据,而不是意识形态。