reference circle of wormwheel

例句：

1. 1. Thedesign of the reference circle is crucial forthe accuracy of the measurement.
   参考圆的设计对于测量的准确性至关重要。
2. 2. The engineer used thereference circle to check the accuracy of themachine.
   工程师使用参考圆来检查机器的准确性。
3. 3. The reference circle was used to measurethe distance between two points on the surfaceof the earth.
   参考圆被用来测量地球表面两点之间的距离。