This document discusses the simple past and present perfect tenses in English grammar. It provides examples of how to form the simple past of regular and irregular verbs, as well as the basic structure of the present perfect using the auxiliary verbs "have" and "be". The document also notes that early Modern English used both "have" and "be" as perfect auxiliaries, while modern English always uses "have", except for some intransitive verbs of motion or change of state which can take "be" in other languages. Formulas for the positive, negative and interrogative forms of the present perfect are also provided.