The continuity of life and its uses:Knowledge of surface change and mineral resources:
Bicycles, clocks and watches, all kinds of mechanical products are basically there. I wonder if you have any in your circle of life
The surface changes in Zhang Heng s seems to be inside.With regard to mineral resources, many of the mining machinery and crushing machines are gear.
The continuation of life, that is, the birth of children, about the use of gear in love, in the Stephen Chow movie want to have a device.
Watches, clocks, fans shake the head, air conditioning pendulum, bicycle speed change, car transmission, washing machines, fitness equipment in the District, these are there.