A person may cause evil to others not only by his actions but by his inaction, and in either case, he is justly accountable to them for the injury.
真正的挑战不在于解方程,而在于理解解的含义。
发展挑战没有放之四海而皆准的解决方案。
教学只是教育的脚手架;真正的建筑是由孩子自己完成的。