。
She turned off all the lights at ten o'clock.
Literal
She [topic-は] ten-o'clock [at-に] lights [object-を] all turned-off.
明かりを消す (to turn off the lights) is a natural collocation — 消す means to extinguish, turn off, or erase. 全部 (all) modifies the action: she turned off every light. 十時に uses に to mark the specific point in time. A simple domestic action that demonstrates basic time + action sentence structure.