plunger duster

例句：

1. 1.The ancient city of Rome was built on a hill, with a powerful plunger duster in its center.
   古罗马城建在一座山上，其中心有一个强大的投石机。
2. 2.In ancient times, the plunger duster was used to clear rivers and lakes.
   古代，投石机被用来清理河流和湖泊。
3. 3. The plunger duster was a crucial tool for military defense during the Middle Ages.
   投石机是中世纪军事防御的关键工具。