5. Choose the correct answer. 1. I have seen / saw the doctor. I have seen / saw him two hours ago. 2. My friend has been / was there last winter. 3. The postman has brought / brought a letter for you. He has brought / brought the letter half an hour ago. 4. We have lived / lived in Tokyo in 1978. He has lived / lived in that town for some time. 5. The student has caught / caught a cold and he stays in bed. 6. Mike has missed / missed two days. He has missed / missed two days last week. 7. Have you ever made / Did you ever make mistakes in your English tests? 8. I have never seen / never saw a ghost. 9. We have already been / were already there and we don't want to go again. 10. The rain has stopped / stopped an hour ago.

Решение:

В данном упражнении необходимо выбрать правильную форму глагола (Present Perfect или Past Simple) в зависимости от контекста.

1. I saw the doctor. I saw him two hours ago. (Прошедшее конкретное время, указанное обстоятельством времени 'two hours ago'.)
2. My friend was there last winter. (Прошедшее конкретное время, указанное обстоятельством времени 'last winter'.)
3. The postman has brought a letter for you. He brought the letter half an hour ago. (В первом случае подразумевается результат действия, поэтому Present Perfect. Во втором случае 'half an hour ago' - конкретное время в прошлом, поэтому Past Simple.)
4. We lived in Tokyo in 1978. He has lived in that town for some time. (В первом случае 1978 год - конкретное время в прошлом, поэтому Past Simple. Во втором случае 'for some time' - длительность, поэтому Present Perfect.)
5. The student has caught a cold and he stays in bed. (Результат действия, который влияет на настоящее время - он болеет сейчас.)
6. Mike has missed two days. He has missed two days last week. (В обоих случаях речь идет о конкретном периоде в прошлом - 'last week', поэтому Past Simple.)
7. Have you ever made mistakes in your English tests? (Вопрос об опыте, поэтому Present Perfect.)
8. I have never seen a ghost. (Вопрос об опыте, поэтому Present Perfect.)
9. We have already been there and we don't want to go again. (Результат действия, который имеет значение для настоящего, поэтому Present Perfect.)
10. The rain has stopped an hour ago. (Конкретное время в прошлом - 'an hour ago', поэтому Past Simple.)

Ответ: 1. saw / saw; 2. was; 3. brought / brought; 4. lived / has lived; 5. caught; 6. missed / missed; 7. made; 8. seen; 9. been; 10. stopped