There are mistakes with verb tenses in these sentences. Find the mistakes and correct them.
O By the time they had got to the party, most of the guests had gone home.
1 It wasn't until Susan had explained that we had understood our mistake.
2 Eventually we had realised what a funny situation it was.
3 After waiting for a bus for more than half an hour we were deciding to get a taxi.
4 As soon as I had left the house, I realised that I had forgotten my keys.
5 I had been sleeping soundly when I had woken up to see a dark shape in the bedroom doorway.
6 I was studying all night while everyone else had slept.​