Complete the sentences with the correct passive form of the verbs

1. In my opinion, more research into the new pills
   [ ] before people started buying them.
2. Their sleep
   [ ] by any noise.
3. I really doubt that wild animals
   [ ] in the zoos safely.
4. It is evident that the results of the exams
   [ ] before they were revealed.
5. Some doctors have an opinion that not all health myths
   [ ] completely.
6. Do you think most smokers
   [ ] to stop smoking by using medicine?
7. They
   [ ] to by the food industry for a long time about healthy products they need.
8. Some modern fashion styles
   [ ] in the past.