Past perfect continuous sentences
1.They had been playing soccer until they were both tired.
2. I had been looking forward to my vacation until I had to cancel it.
3.Ann had been dreaming until she woke up in the middle of the night.
4.Mike had been watching a DVD until I got home.
5.I had been reading a book on the bus until my friend got on the bus.
6. I had been looking for a flight ticket until I found a good one (or 'the right one', or 'the perfect one').
7. I had been doing my homework before the class started.
8. I had been writing a letter before the hockey game started.
Only a couple of small corrections. Well done!