Ответы
1. The boys had been assembling the bicycle for more than two hours when their father came and said that they would have to disassemble everything again, since they had assembled it incorrectly. 2. I had been working for a long time when my brother came. 3. It had been raining for two hours when I left the house. 4. Although the sun was shining, it was still cold, as it was snowing heavily for two hours. 5. She had been asleep for three hours when we got home. 6. His sister had already lived there for three years when the war began. 7. She worked in the factory without rest for a long time. 8. He looked very tired when I came to him because he had been preparing for exams for several days. 9. They sailed for ten days when they finally saw land. 10. By 12 o'clock he had already spoken for over an hour; B it was a very long speech. 11. When I arrived at the library, he was working on a report for over two hours. 12. She was working for an hour and a half when Nick said he could no longer work.