levers

例句：

1. 1. The engineer used a lever to lift the heavy box.
   工程师使用杠杆把沉重的箱子抬起来。
2. 2. The scientist discovered a new lever that could increase efficiency.
   科学家发现了一种新的杠杆，可以提高效率。
3. 3. The farmer used a lever to plow his fields efficiently.
   农民使用杠杆高效地翻耕他的田地。