挑战让生活变得有趣；克服挑战让生活变得有意义。
Challenges are what make life interesting; overcoming them is what makes life meaningful.
经济学家的理想角色是澄清社会面临的替代方案，而不是为社会做出选择。
The challenges of today are the opportunities of tomorrow—if we approach them with the right mindset.
真正的可持续性意味着为子孙后代留下比我们发现时更好的土地。