Idioms can be a powerful linguistic tool only when they are used in the right way in the right places.
leave (something) on or leave on (something)
to leave something running or operating
I always leave the lights on when I am working in the house.
List of common idioms, their meanings and examples of their usage in sentences
An idiom is defined as - a group of words in a fixed order that has a particular meaning that is different from the meanings of each word on its own.