Ответ:

  1. I have never been to London.
  2. They have worked here for three years.
  3. He broke his leg last winter.
  4. We have already finished the project.
  5. She studied French when she lived in Italy.
  6. I haven’t seen him since Monday.
  7. They have bought a new car this year.
  8. He has lived in this city all his life.
  9. We have known each other for a long time.
  10. She has visited this museum several times.

Past Simple употребляется с указанием завершённого времени в прошлом: last winter, when she lived. Present Perfect — когда важен результат или период продолжается до настоящего момента: for three years, since Monday, all his life, this year.