Every Saturday I’ll give you a couple of idioms to learn. An idiom is a saying or phrase whose meaning cannot be taken from the literal meanings of the words.
rat (out) on: desert or betray someone
Example:
Although the teacher threatened all the boys with punishment if they didn’t tell who pulled the prank, they stuck together and refused to rat on Mark.
rat race: rushing around, confusing way of living that does not seem to have a purpose
Example:
Someday I’m going to save enough money to retire to Montana and get away from the rat race.