What were they doing at the party? Where/sit? What/wear? What music/listen to? What dances/do(perform)? What dish/children/make?

What were they doing at the party? — Что они делали на вечеринке?

Where were they sitting? — Где они сидели?

What were they wearing? — Что были они одеты?

What music were they listening to? — Какую музыку они слушали?

What dances were they performing? — Какие танцы они исполняли?

What dish were children making?— Какое блюдо дети делали?

Who was cooking fish? — Кто готовил рыбу?

Past Continuous is formed with the help of the past form of the auxiliary verb to be (was, were) and ending – ing.

Was is used for singular and were is used for plural.