8. The river water is severely polluted, mostly …………… the dumping of raw sewage. A. because B. so C. lead to D. due to 9. If there ……….…… fewer cars on the road, there would be less pollution. A. is B. are C. was D. were 10. Unless you …………….. all of my questions, I can’t do anything to help you. A. answer B. answered C. are answering D. would answer