英文說明:A roller harrow was used after plowing and harrowing to flatten and smooth the fields. It is built in a rectangular shape with a toothed roller in the middle. This implement was pulled by an ox during use and the farmer stood atop the wooden frame. When the ox walked forward, a clacking sound was heard. The roller was made of hard wood to avoid rot. In later times, iron was used to make the rollers. However, iron rusted.