。
She turned on the light.
Literal
She [topic-は] light [object-を] turned-on.
明かりをつけた — つける means 'to turn on' (lights, appliances). 明かり (あかり, 'light, lamp') is a native Japanese word. The opposite is 明かりを消す ('to turn off the light').
。
She turned on the light.