The document discusses idioms, which are phrases with meanings that cannot be understood from the literal definitions of the individual words. It provides English examples of common idioms and their literal meanings, along with the corresponding Spanish idioms. Some idioms discussed include "add fuel to the fire," "bite your tongue," "break a leg," "a piece of cake," "all bark and no bite," "Elvis has left the building," "beating around the bush," and "hold your horses." The document tests the reader to guess the meanings of the idioms and then provides the Spanish translations.