8.We (listen)………listened……….to the radio when it stopped (work)……working………..

9.I (not hear)……haven't heard……………..of him since we last met

10.He (serve)……served……..in the army from 1960 to 1969

11.It started to rain while you (sleep)………was sleeping…………….

12.The doctor (be)…………have been ……..here since 7 o’clock

13.Four films (make)……have made……….by Michal so far