只有兩格：開，或關
兩個意思用的是同一顆開關，差別只在它按在機器上，還是按在一段時間上。
adjective · B1
Used about a switch or button that has two positions only: press or flip it one way and the machine starts working, press or flip it back and the machine stops.
開關的、電源的
核心畫面
One way to picture on-off: a switch with two positions and nothing in between. Up, and the machine runs; down, and it stops. There is no half, no slow fade, no middle setting. The word takes the two words printed on the machine and ties them together, and everything it describes keeps that shape — two states, and a jump from one to the other.
on-off 可以想成一顆只有兩格的開關：往上，機器就動；往下，就停。沒有一半，沒有慢慢變弱，中間沒有第三格。這個詞…更多收起
on-off 可以想成一顆只有兩格的開關：往上，機器就動；往下，就停。沒有一半，沒有慢慢變弱，中間沒有第三格。這個詞把機器上印的那兩個字綁在一起，所以它形容的東西也保持同一個樣子——兩種狀態，而且是用跳的，不是用滑的。One branch