tiller rotro

例句：

1. 3.
   农业机械
2. 1. The farmer used a tiller to break the soil.
   农民用犁头翻土。
3. 2. The rotor on the helicopter is responsible for lifting off.
   直升机上的旋翼负责起飞。
4. 3. The new tiller has made farming easier.
   新型犁具使耕作变得更容易了。