。
She flipped the switch.
Literal
She [topic-は] switch [object-を] pressed.
A bare-bones SOV sentence — topic + object + transitive verb in the past. スイッチ is a Meiji-era English borrowing that has fully naturalized; in modern usage it covers everything from light switches to game-controller toggles to figurative 'gear shifts' (頭のスイッチを切り替える, 'switch mental gears'). Note that 押す covers both pushing and pressing — Japanese doesn't separate the two the way English does, so a button, a switch, or even a doorbell all get the same verb.