Complete these sentences with appropriate prepositions. 1. Many scientists are concerned___________ the environmental problems today. 2. The decrease___________ air pollution was dramatic last year. 3. They were well aware___________ the problem. 4. I’ve come___________ ___________ an idea about the new project. 5. Radiation can lead ___________ childhood cancer. 6. Households dump waste___________ lakes and rivers. 7. Oil spill ___________ ships in oceans and rivers makes many underwater animals die. 8. Nothing would prevent him___________ acting for environment. 9. Some local people use contaminated water___________ cooking. 10. The residents complain___________ the bar owner ___________ its noise.