The age was marked by increased specialization and the invention of the wheel and the ox-drawn plow.
青铜时代还出现越来越多的分工，并且发明了车轮及牛拉的耕犁。
2
This paper introduces the structure and working principle of the crank rocker transposition mechanism of depth wheel on two way alternative plow and the process of optimizing its parameters.
介绍了全翻转式双向犁的曲柄摇块式限深轮换位机构的结构、工作原理及参数优化设计过程。
3
1LF hydraulic reversible plow is mounted with four-wheel tractor; it is used for the loam, sand loam , cultivated and dry land , it can finish the furrowing work in double way.