Образуется перестановкой вспомогательного глагола was/were перед подлежащим:
$\text{Was / Were}+\text{subject}+\text{verb-ing}?$
Правило согласования: was — для I/he/she/it; were — для you/we/they.
Для вопроса с вопросительным словом:
$\text{Wh-word}+\text{was/were}+\text{subject}+\text{verb-ing}?$
Примеры:
- Was she sleeping?
- Were they playing football?
- What were you doing at $8$ o'clock?
Краткие ответы: Yes — "Yes, he/she/it was." No — "No, they weren't."