<human>:  What is the origin of the idiom "Don't cry over spilled milk"?
<bot>: The origin of the idiom "Don't cry over spilled milk" is uncertain, but it is thought to have originated in the late 1500s-early 1600s. The phrase was first recorded in print in 1639 in John Ray's collection of English Proverbs. By the 1700s, the phrase was a well-known proverb, with various similar versions being used, such as "weeping for spilt drink won't fill the pitcher again" and "no crying for spilt liquor". The idiom is a reminder not to dwell on things that cannot be undone.