1.I (was sitting/am sitting/sat) on a bench and reading an article when John (was coming up/came up/had come up) to me.
2.When Sara (arrived/was arriving/have arrived) at the airport, she saw some flight attendants for the first time in her life.
3.Jessica (had watched/was watching/watched)a film when she heard somebody knocking on the door.
4.Yesterday Nick (was going/have gone/went)to the library, then he (have had/was having/had)lunch, and after that he (was meeting/met/had met)his supervisor.
5.Andrew (was spraining/sprained/have sprained)his ankle when he (was fleeing/flee/fled)from the police officers.
6.When the manager (was entering/entered/had entered)the office, everybody (danced/was dancing/were dancing).
7.On holidays we (have gone/were going/went)hiking, (were swimming/swam/have swum)in the lake and visited the historic centre of the town.