1. These documents were saving as a starting point. Здесь, возможно, опечатка, но можно перевести так: Эти документы были спасительными вначале.
were saving - Past Continuous
2. About 100 thousand people will be working at the Olimpic Games in 2014.
will be working - Future Continuous
3. The world is changing faster now than ever before. is changing - Present Continuous