Simple past or past perfect? Complete the sentences

1. The meeting ......... when i.......... (alredy start; arrive)
2. Thecar .......... down because i ........ to put oil in (break; forget)
3. I ....... Mary for the first time thirty years ago (meet)
4. After our conversation i........... everything that she..........(forget;say)
5. The house was empty. Everybody ....... out. (go)
6. When he ...... work he ......... out for a walk (finish;go)