2. When the cyclone (to begin) ____ Dorothy and Toto (to play) ____ in the yard.

Перевод задания: Когда начался циклон, Дороти и Тото играли во дворе.

Краткое действие «начался» — Past Simple, длительное действие в этот момент — Past Continuous: began, were playing.

When the cyclone began, Dorothy and Toto were playing in the yard.

Ответ: began, were playing.