Ответ:
Перевод: By the time the bus arrived, we had already been waiting at the bus stop for an hour.
Длительное действие, начавшееся до приезда автобуса, передано формой Past Perfect Continuous.
Перевод: By the time the bus arrived, we had already been waiting at the bus stop for an hour.
Длительное действие, начавшееся до приезда автобуса, передано формой Past Perfect Continuous.