可持續(xù)性必須成為我們開采每一塊石料的核心，否則我們什么也不該開采。
Every child should have mud pies, grasshoppers, water bugs, tadpoles, frogs, mud turtles, elderberries, wild strawberries, acorns, chestnuts, trees to climb, brooks to wade in, water lilies, woodchucks, bats, bees, butterflies, various animals to pet, hayfields, pine-cones, rocks to roll, sand, snakes, huckleberries and hornets; and any child who has been deprived of these has been deprived of the best part of education.
不如意的事要能排遣，日子清苦要能守得住，無(wú)道理的事要受得住，憤怒產(chǎn)生時(shí)要忍耐，欲望產(chǎn)生時(shí)要克制。