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。
Machinery and labor-saving devices are only valuable as they serve to reduce the cost of manufacture.
The poet is a man who plants a tree and then sits in its shade.
Darkness cannot drive out darkness: only light can do that. Hate cannot drive out hate: only love can do that.
The history of men is the history of their crimes.