A method of solution is perfect if we can foresee from the start, and even prove, that following that method we shall attain our aim.
如果我们从一开始就能预见，甚至证明，遵循某种方法我们将达到我们的目标，那么这种解决方法就是完美的。
Every day is a new opportunity to change your life.
可持续性不仅仅是植树造林；而是确保我们今天采取的每一个行动都不会损害未来。