zero offset optical square

例句：

1. 1.This zero offset optical square is used to measure the distance between two points on a map.
   这个零偏移光学方格用于测量地图上两点之间的距离。
2. 2. The zero offset optical square was used to calculate the angle between the lines.
   零偏移光学方格被用来计算两条线之间的夹角。
3. 3. The zero offset optical square was used to verify the accuracy of the measurements.
   零偏移光学方格被用来验证测量的准确性。