PRACTICE 1. Environmental pollution has led to the disappeasence of many species of plants and animals from our planet. (disappear) 2. Some people have very firm belieb (believe) in the existence of UFOs. (mysterious) 3. The exact origin of the universe remains a 4. The evidence of mysterious UFO flying objects is overwhelming. (identify) A 5. The books on UFOs are always in because I'm very the UFOs. (interest) 6. People are talking about the mysterious circles on the fields in Great Britain. (mystery) ad 7. They are too young and inexperienced to recognize the danger of drugs. (experience) 8. He is an experienced doctor who just graduated from the medical school last year. (experience) (science) 9. He was one of the greatest Scien of the time. 10. Do you believe in the existent of UFOs? (exist) (entertain) 11. For some people UFOs only exists in films for entertainment 12. I find her story about UFOs hardly believable. (believe) A C