这份古老的地图上有些空白处，可能是由于年代久远而缺失了部分信息。

There are several ___lacunae in this ancient map, likely due to missing information over time.

显微镜下可以观察到骨骼组织中的微小空隙。

Under the microscope, tiny ___lacunae can be seen in the bone tissue.

这篇报告指出了我们在气候变化研究中的几个重要知识空白。

The report highlights several key ___lacunae in our climate change research.