The sky darkened suddenly.
The theatre darkened to signal the beginning of the show.
In the east, the sky began to darken.
The room darkened as the sun set.
The family's precious silver darkened from disuse.
Jewely darkens over time without maintenance.
The tablecloth was darkened by spilled red wine.
Mom darkened the room so we could sleep.
John darkened the house by covering the windows.
The house darkened suddenly when the lightbulbs burned out.
The army ranger darkened his torch to move unnoticed.