实现明天理想的唯一障碍是今天的疑虑。

The work is a kind of mapping.

What is the difference between a Turing machine and the modern computer? It's the same as that between Hillary's ascent of Everest and the establishment of a Hilton hotel on its peak.

创新不是一种选择；它是煤炭行业生存的必要条件。