The document discusses the Spanish imperfect tense. The imperfect tense describes ongoing or habitual past actions, such as "I used to...". It explains how to form the imperfect of regular -ar, -er, and -ir verbs by dropping the infinitive endings and adding new endings. It provides examples of the irregular verbs ser and ir in the imperfect. It also presents useful expressions that can be used with the imperfect tense, such as "many times", "every day", and "always".