Turn off the lights when you leave.

Meaning: This means to stop the operation of the devices that produce artificial light, at the time that the person being spoken to goes away from a place. It's like saying, Stop the operation of the devices that produce artificial light, at the time that you go away from a place.

Choice of Words: Turning off means to stop the operation of something. Lights are devices that produce artificial light. When means at the time that. Leave means to go away from a place. When you put them together, "Turn off the lights when you leave" is a request to stop the operation of the devices that produce artificial light, at the time that the person being spoken to goes away from a place.

Alternative Expressions

Related Expressions

• Turn off the lights when you leave a room.
• Please turn off the light before you leave.
• Turn off the light when you leave the room.
• Turn off the lights.
• Turn off the lights when leaving a room.
• Turn lights off.
• Turn off lights.
• Turn on the lights.
• Lights turn on.
• Please close the window before you leave.