1. They had already had breakfast before they arrived at the hotel.

2. She had finished writing the composition by 10:00 this morning.

3. He told me that there had been an argument between them.

4. And this semester, we have learned the past tense, the past perfect tense and the future tense and so on.

5. They said that production costs had been reduced.

6. All the tickets had been sold out when they arrived.

7. We had hardly reached the school before it began to rain.

8. By the time I got to the bus stop, the bus had already left.

9. Eric died a few days ago and these years, he had lived as a recluse.

10. He died, though great efforts had been made to save his

11. I hadn’t learned any English before I came here.

12. 如He said he had never been to the city since he left there ten years ago.

13. She would have come if she hadn’t been so busy.

14. When I woke up, it had already stopped raining.

15. I had finished the composition before supper.

希望这些例句能帮助你更好地理解和运用过去完成时。