index reference line

例句：

1. 1. The engineer used the indexreference line to measure the distance between twopoints on the map.
   工程师使用索引参考线测量地图上两点之间的距离。
2. 2. The scientistdrew an index reference line on the graphto indicate the trend of the data.
   科学家在图表上画了一条索引参考线，以指示数据的趋势。
3. 3. Thearchitect designed a unique indexreference line that would enhance theoverall aesthetics of the building.
   建筑师设计了一条独特的索引参考线，以增强建筑的整体美学。