Ответ:
We were swimming when it began raining.
She was writing a test when the bell rang.
Granny was lying on the sofa when we came.
I was taking a shower while my mother was cooking.
They were travelling about Europe while Dan was spending his holidays in Africa. (или наоборот Африка и Европа)
Tom was dressing at 5 o'clock yesterday.
Jill and Jim were going to the theatre when we met them.
Объяснение: