Here is a summary of the key points regarding the difference between the past simple and present perfect tense:

• Core Difference: The difference between the past simple and present perfect usually boils down to how time and connection are viewed.
• Past Simple:
  • Acts like a closed box where the event is finished and the time period is over.
  • Refers to a specific dot in the past that is completely separated from the present.
  • Focuses on when an event happened (e.g., "I lost my keys yesterday" or "I visited Paris in 2019").
  • Used with finished time periods such as "yesterday," "last week," or "in 1999".
• Present Perfect:
  • Builds a bridge between the past and the present moment.
  • The action started in the past, but it still touches or affects the present reality (e.g., "I have lost my keys" implies you currently cannot get into your house).
  • Used with open time periods that are still ongoing, such as "today," "this week," or "in my life".
  • Expresses life experiences up to the present moment (e.g., "I have visited Paris") because your life is not finished.