When you attack coal, you attack middle America.

There is danger from all men. The only maxim of a free government ought to be to trust no man living with power to endanger the public liberty.

The past is a ghost, haunting the present.

科学无国界，因为知识属于人类，是照亮世界的火炬。

投资于我们的员工与投资于设备同样重要。

Progress happens when we stop blaming and start solving.

机械和节省劳力的装置只有在降低制造成本时才具有价值。

智慧就是适应变化的能力。