波多野结衣办公室双飞_制服 丝袜 综合 日韩 欧美_网站永久看片免费_欧美一级片在线免费观看_免费视频91蜜桃_精产国品一区二区三区_97超碰免费在线观看_欧美做受喷浆在线观看_国产熟妇搡bbbb搡bbbb_麻豆精品国产传媒

Plow (6000 BC)

The domestication of animals such as oxen provided mankind with the pulling power needed to develop the first plows. They consisted of a frame holding a vertical wooden stick that was dragged through the topsoil -- and are still used in many parts of the world.

犁（公元前6000年）

馴化牛等動物為人類制造首批耕地用的犁提供了牽引力。犁由一個框架組成，框架上支撐著一根垂直的木棍，通過牛拉犁，木棍就可以劃過表層土壤。如今全球很多地區(qū)仍在使用。