Раскройте скобки, употребляя глаголы в Present Perfect или Past Indefinite. 1. I (meet) two of my friends today. I (meet) them on my way to school. 2. A month ago my uncle (build) a new house in the country. We (visit) it recently and (enjoy) ourselves very much. 3. He (forget) to close the window when he (leave) the house. 4. He (write) several letters this week. 5. Where Helen (go)? I don't see her here. — She (go) home an hour ago. 6. When the concert (to begin)? 7. I don't think I ever (to see) such a beautiful garden as this one. 8. Jack London (to be born) in San Francisco in an extremely poor family. 9. You (to read) many books by Jack London? 10. How careless you are! You (to break) your mother's favourite cup.

Вот правильное разборка предложений с использованием Present Perfect и Past Indefinite:

1. I have met two of my friends today. I met them on my way to school.
   (Первое действие относится к сегодняшнему дню и ещё актуально — Present Perfect, второе — конкретный факт в прошлом — Past Indefinite.)

2. A month ago my uncle built a new house in the country. We have visited it recently and have enjoyed ourselves very much.
   (Строительство произошло в прошлом — Past Indefinite, визит и удовольствие — недавно, актуально сейчас — Present Perfect.)

3. He forgot to close the window when he left the house.
   (Оба действия завершены в прошлом — Past Indefinite.)

4. He has written several letters this week.
   (Неделя ещё не закончилась, действие имеет результат в настоящем — Present Perfect.)

5. Where has Helen gone? I don't see her here. — She went home an hour ago.
   (Первое — результат действия в настоящем — Present Perfect, второе — конкретное время в прошлом — Past Indefinite.)

6. When did the concert begin?
   (Конкретное время в прошлом — Past Indefinite.)

7. I don't think I ever have seen such a beautiful garden as this one.
   (Опыт до настоящего момента — Present Perfect.)

8. Jack London was born in San Francisco in an extremely poor family.
   (Произошло в прошлом, конкретный факт — Past Indefinite.)

9. Have you read many books by Jack London?
   (Вопрос про опыт до настоящего момента — Present Perfect.)

10. How careless you are! You have broken your mother's favourite cup.
    (Результат действия актуален сейчас — Present Perfect.)

Если хочешь, я могу сделать короткую шпаргалку по правилам, как отличать Present Perfect от Past Indefinite в таких предложениях — это сильно облегчает такие упражнения.