生活若无波折险阻，就会过于平淡无奇。

The best designs are those that solve problems elegantly without drawing attention to themselves.

Leadership is about making tough decisions today that will define tomorrow's legacy.

教师必须为形成较好人类而献出一切。

离散数学和连续数学之间的相互作用是一些最有趣的问题所在。