Сначала вопросительное слово, например, what? where? + глагол was (для местоимений he,she,it)или were (для всех других) + подлежащее + основной глагол с окончанием -ing. Если вопр. слова нет, то вопрос начинаем сразу со вс глагола was или were!
Например: Was he reading the book? What were you eating yesterday?
Формула past continuous-was или were и глагол с окончанием ing
И получается
Were they planning the picnic?
