rack-jack

例句：

1. 1. The engineer used a rack-jack to lift the heavy load.
   工程师使用一台起重机来提升沉重的负载。
2. 2.The workers were busy lifting the materials for the construction site.
   工人们忙于为建筑工地搬运材料。
3. 3. The crane was positioned at the edge of the dock, ready to lift the cargo.
   起重机被放置在码头的边缘，准备吊起货物。