1. Watching documentary films we get to know many helpful things for our life.
2. Students need to watch educational films at school.
3. Our film industry hasn't yet made films that won the world's grand prize.
4. Motion pictures are both art and industry.
5. Among American actors, who/which one do you like best?
6. She looks pretty, but does she actually act well?
This is JUST my opinion, not necessarily correct.
I'd wait for answers from native speakers.