В1. She started cleaning after everybody had left the house.В 2. They had bought the tickets before they went to the theatre.В 3.Anna passed all her exams because she had studied hard.B 4.David had taking the dog for a walk before he went to bed.В 5. When he arrived at the station the train had already left.B 6.They had made a lot of jam because they had gathered a lot of apples.B 7.He went for a walk after he had done all his work.B 8.Kate had cooked pies before she went to bed.