The document discusses the formation of the perfect tense in Latin verbs. It explains that the stem for the perfect tense comes from the third principal part of the verb, with the final "i" removed. This stem is then combined with standard perfect endings to form the perfect tense of any Latin verb. The perfect tense in English translates to actions completed in the past, such as "I have loved", "I did love", or "I loved". All Latin verbs form their perfect tense using the same process of taking the third principal part and adding the appropriate ending.