4. Complete the sentences with the Past Simple or Past Continuous forms of the verbs in brackets: 0) I was tidying my room when I found my keys. 1) While they ___ (climb) the mountain, they had a bad accident. 2) What were you watching on TV when I ___ (call) you? 3) We ___ (put) on our coats when it started to snow. 4) While mum was waiting for the bus, she ___ (see) her best friend. 5) I ___ (not sleep) when Dad arrived home from the airport.

1. While they were climbing the mountain, they had a bad accident. — Пока они поднимались на гору, с ними произошёл несчастный случай.
2. What were you watching on TV when I called you? — Что ты смотрел по телевизору, когда я тебе позвонил?
3. We were putting on our coats when it started to snow. — Мы надевали пальто, когда начался снег.
4. While mum was waiting for the bus, she saw her best friend. — Пока мама ждала автобус, она увидела свою лучшую подругу.
5. I wasn't sleeping when Dad arrived home from the airport. — Я не спал, когда папа приехал домой из аэропорта.

Past Continuous используется для длительного действия, происходившего в определённый момент, а Past Simple — для краткого завершённого события.