3.
1 When I got to the party , it had already started raining.
2 I had just finished writing my essay, when Laura phoned.
3 Jason opened the window, a white sheet of snow covered the ground.
4 Sue gave me a call to stay they hadn't buy the necessary sportwear yet.
5 Lucy couldn't remember the fact her friend had mentioned the day before.
6 When I met Fohn, I understood that I had seen him before.
7 When the second group of tourist arrived in London, the first group had already left .