可持续性不是选择，而是我们对下一代的责任。
Sustainability isn't an option; it's our responsibility to the next generation.
To write is to breathe, to live, to exist beyond the confines of time.
I'm a control freak. I admit it.
没有道德或不道德的书，只有写得好或写得差的书。
学习数学的唯一方法就是做数学。
你给予的越多，得到的就越多。