Ответ:

Время выбирается по обстоятельствам: указание на конкретное завершённое время (last year, in 2020, yesterday, two days ago) требует Past Simple; слова already, just, never, since обычно требуют Present Perfect.

  1. I saw that film last year.
  2. She has already finished her homework.
  3. They visited London in 2020.
  4. He has just come home.
  5. We went to the park yesterday.
  6. I have never been to Italy.
  7. My brother broke his phone two days ago.
  8. They have lived in this city since 2015.

Ответ: 1) saw; 2) has already finished; 3) visited; 4) has just come; 5) went; 6) have never been; 7) broke; 8) have lived.