3 All evening the Cratchits sat / were sitting together and ate / were eating the holiday dinner.

were sitting / were eating Объяснение: Все вечер Кратчиты сидели и ели праздничный ужин. Оба действия происходили одновременно и в течение некоторого времени, поэтому используется Past Continuous (were sitting, were eating).