The document discusses the differences between using the simple past and present perfect tenses. The simple past is used for specific past times and implies remoteness, while the present perfect emphasizes the present result of an event and is used for unfinished or ongoing situations. Some temporal expressions are commonly used with either tense, while others tend to occur more frequently with one tense versus the other. The choice of tense also depends on whether the context defines an event as a completed historical period or an ongoing one.