She smiled unexplainably when she heard the old melody, as if remembering something distant.

The unexplainability of the ancient ruins frustrated every archaeologist who investigated them.

The scientist was frustrated by the unexplainableness of the sudden temperature drop during the experiment.

Her unexplaining silence made everyone uneasy.

The scientist encountered an unexplainable anomaly in the data that challenged every theory she knew.

The scientist presented data about the unexplained anomaly at the conference.

Pilots reported multiple unexplained aerial phenomena over the coastal city last night, prompting an official investigation.

The research team released footage they claimed showed an unexplained aerial phenomenon hovering over the coastline.

Researchers are studying sudden unexplained death syndrome to identify underlying genetic causes.