Прочитайте текст. Запишите в поле ответа цифру 1, 2, 3 или 4, соответствующую выбранному вами варианту ответа.
Why did observers frequently remark that the sky was darkened for days at a time?
- Because birds arrived at dusk.
- Because birds usually migrated in cloudy weather.
- Because birds were of dark colour.
- Because flocks moved in an almost solid unit.
Ответ: 4