15. While the children ___ (play) outside, their mother ___ (clean) the house.

Перевод задания: Раскройте скобки и поставьте глаголы в Past Simple или Past Continuous.

While the children were playing outside, their mother was cleaning the house.

Пока дети играли на улице, их мама убирала дом. Два действия происходили одновременно.