2. Choose the correct option. 1) I was running for the bus when I dropped / was dropping my phone. 2) Jack fell asleep while he watched / was watching the film. 3) We were walking home when the wind started / was starting to get stronger. 4) My cousins stayed / were staying in Japan when the earthquake happened. 5) The bear appeared / was appearing while we were walking down the mountain. 6) The postman came / was coming while we were having breakfast.

Перевод задания: Выберите правильный вариант.

1. I was running for the bus when I dropped my phone. (Я бежал за автобусом, когда уронил телефон.) — Краткое завершённое действие употребляется в Past Simple.
2. Jack fell asleep while he was watching the film. (Джек заснул, пока смотрел фильм.)
3. We were walking home when the wind started to get stronger. (Мы шли домой, когда ветер начал усиливаться.)
4. My cousins were staying in Japan when the earthquake happened. (Мои двоюродные братья и сёстры находились в Японии, когда произошло землетрясение.)
5. The bear appeared while we were walking down the mountain. (Медведь появился, когда мы спускались с горы.)
6. The postman came while we were having breakfast. (Почтальон пришёл, пока мы завтракали.)

Длительное фоновое действие выражается Past Continuous, а краткое событие, произошедшее на его фоне, — Past Simple.