Complet the sentences is past perfect continuous 1.they (not/wait) at the station for 90 minutes when the train finally arrived. 2.we (wait for) her ring for two hours and them we found it in the bathroom. 3. i (walk) for a long time, when it suddenly began to rain. 4. how long (study/ she) english before she went to london?

1.They had not been waiting at the station for 90 minutes when the train finally arrived.
2.We had been waiting for her ring for two hours and then we found it in the bathroom.
3. I had been walking for a long time, when it suddenly began to rain.
4. How long had she been studying English before she went to London?

1. had not been waiting.
2. had been waiting for.
3. had been walking.
4. how long had she been studying...