Learning is any change in a system that produces a more or less permanent change in its capacity for adapting to its environment.
学习是系统中产生的任何变化，这些变化或多或少会永久性地改变其适应环境的能力。
乐观是一种可以学习的技能。一旦你学会了它，你就能在各个方面改善你的生活。
I think the most important thing in life is to be true to yourself.