开关

HSK 6

kāiguān

switch; toggle

gas valve; to open the city (or frontier) gate; to open and close; to switch on and off

开关电源

kāiguān yuánlǐ

Turn on/off power supply

他不小心按错了开关。

Tā bù xīnyíngàn cuò le kāiguān.

He inadvertently pressed the wrong switch.