22 Jackie .................... (take) notes during the lesson while other students were just listening.

Для образования Past Continuous необходимы вспомогательный глагол to be в прошедшем времени (was/were) и основной глагол в форме Present Participle (с окончанием -ing).

Так как подлежащее выражено именем собственным "Jackie" (она), то вспомогательный глагол ставим в единственном числе - was.

Глагол take ставим в форму Present Participle - taking.

Получаем: Jackie was taking notes during the lesson while other students were just listening.

Ответ: Jackie was taking notes during the lesson while other students were just listening.