If we want to protect forests, we must first understand them.

I think goals should never be easy, they should force you to work, even if they are uncomfortable at the time.

懒惰奢侈，招来贫困；勤劳节俭，累积财富。

要理解现在，必须挖掘过去。

登上梯子顶端的唯一方法就是一步一步往上爬。

解析：意与知、物紧密相连。