lengthening bar

例句：

1. 1. The lengthening bar is used to adjust the height of the table.
   拉长杆用于调整桌子的高度。
2. 2.The engineer used a lengthening bar to adjust the angle of the beam.
   工程师使用拉长杆来调整梁的角度。
3. 3. The lengthening bar was used to measure the distance between two points.
   拉长杆被用来测量两点之间的距离。