screw prop

• 千斤顶

screw prop的用法和样例：

例句

1. Each of the four legs contains a simple screw jack with a thrust bearing that is operated telescopically inside of two tubes.
   四条腿中每个都装有一个简单的螺旋千斤顶，千斤顶中又有一个在两根管道中做伸缩操作的推力轴承。