rocking-arm pump

例句：

1. 1. The rocking-arm pump is used to remove water fromthe well.
   摇臂泵用于从井中抽水。
2. 2. The rocking-armpump was designed to improve efficiency in oilextraction.
   摇臂泵被设计用来提高石油开采的效率。
3. 3. The rocking-armpump is a common tool used by farmersto move soil and water.
   摇臂泵是农民常用的工具，用来移动土壤和水分。