1. I had finished my homework before dinner.

2. By the end of last year, Henry had collected more than a hundred stamps.

3. When we got there, the basketball match had begun.

4. The roads were full of people. We hadn't foreseen that.

5. He had only reached home when a man called to see him.

这些例句展示了过去完成时态在不同情境下的应用，希望对你有所帮助。